| 
         Income Taxes (Tables)
 | 12 Months Ended | 
      
       | 
         Jun. 30, 2014 | 
      
       | Income Tax Disclosure [Abstract] |  | 
      
       | 的时间表Income before Income Taxes, Domestic and Foreign | 
         
          The components of income before income taxes are as follows:
          
          
          
           
            
             
              |  |  
              |  |  |  |  |  |  |  |  |  |  |  |  |  
              | 
                
                | 
                Year ended June 30,
                |  
              | 
                (In thousands)
                | 
                2014
                | 
                
                | 
                2013
                | 
                
                | 
                2012
                |  
              | 
                Domestic income before income taxes
                | 
                $
                | 
                434,336
                | 
                
 | 
                
                | 
                $
                | 
                420,862
                | 
                
 | 
                
                | 
                $
                | 
                607,146
                | 
                
 |  
              | 
                Foreign income before income taxes
                | 
                300,125
                | 
                
 | 
                
                | 
                269,759
                | 
                
 | 
                
                | 
                366,948
                | 
                
 |  
              | 
                Total income before income taxes
                | 
                $
                | 
                734,461
                | 
                
 | 
                
                | 
                $
                | 
                690,621
                | 
                
 | 
                
                | 
                $
                | 
                974,094
                | 
                
 |  | 
      
       | 的时间表Components of Income Tax Expense (Benefit) | 
         
          The provision for income taxes is comprised of the following:
          
          
          
           
            
             
              |  |  
              |  |  |  |  |  |  |  |  |  |  |  |  |  
              | 
                (In thousands)
                | 
                Year ended June 30,
                |  
              | 
                2014
                | 
                
                | 
                2013
                | 
                
                | 
                2012
                |  
              | 
                Current:
                | 
                
                | 
                
                | 
                
                | 
                
                | 
                
                |  
              | 
                Federal
                | 
                $
                | 
                98,937
                | 
                
 | 
                
                | 
                $
                | 
                118,888
                | 
                
 | 
                
                | 
                $
                | 
                (699
                | 
                )
                |  
              | 
                State
                | 
                8,580
                | 
                
 | 
                
                | 
                4,404
                | 
                
 | 
                
                | 
                51
                | 
                
 |  
              | 
                Foreign
                | 
                27,867
                | 
                
 | 
                
                | 
                25,112
                | 
                
 | 
                
                | 
                24,383
                | 
                
 |  
              | 
                
                | 
                135,384
                | 
                
 | 
                
                | 
                148,404
                | 
                
 | 
                
                | 
                23,735
                | 
                
 |  
              | 
                Deferred:
                | 
                
                | 
                
                | 
                
                | 
                
                | 
                
                |  
              | 
                Federal
                | 
                22,904
                | 
                
 | 
                
                | 
                (2,552
                | 
                )
                | 
                
                | 
                188,882
                | 
                
 |  
              | 
                State
                | 
                (334
                | 
                )
                | 
                
                | 
                (1,036
                | 
                )
                | 
                
                | 
                3,721
                | 
                
 |  
              | 
                Foreign
                | 
                (6,248
                | 
                )
                | 
                
                | 
                2,656
                | 
                
 | 
                
                | 
                1,741
                | 
                
 |  
              | 
                
                | 
                16,322
                | 
                
 | 
                
                | 
                (932
                | 
                )
                | 
                
                | 
                194,344
                | 
                
 |  
              | 
                Provision for income taxes
                | 
                $
                | 
                151,706
                | 
                
 | 
                
                | 
                $
                | 
                147,472
                | 
                
 | 
                
                | 
                $
                | 
                218,079
                | 
                
 |  | 
      
       | 的时间表Deferred Tax Assets and Liabilities | 
         
          The significant components of deferred income tax assets and liabilities are as follows:
          
          
           
            
             
              |  |  
              |  |  |  |  |  |  |  |  |  
              | 
                (In thousands)
                | 
                As of June 30,
                |  
              | 
                2014
                | 
                
                | 
                2013
                |  
              | 
                Deferred tax assets:
                | 
                
                | 
                
                | 
                
                |  
              | 
                Tax credits and net operating losses
                | 
                $
                | 
                95,492
                | 
                
 | 
                
                | 
                $
                | 
                77,512
                | 
                
 |  
              | 
                Employee benefits accrual
                | 
                97,308
                | 
                
 | 
                
                | 
                83,391
                | 
                
 |  
              | 
                Stock-based compensation
                | 
                17,676
                | 
                
 | 
                
                | 
                37,091
                | 
                
 |  
              | 
                Capitalized R&D expenses
                | 
                12,051
                | 
                
 | 
                
                | 
                34,791
                | 
                
 |  
              | 
                Inventory reserves
                | 
                83,783
                | 
                
 | 
                
                | 
                79,866
                | 
                
 |  
              | 
                Non-deductible reserves
                | 
                41,469
                | 
                
 | 
                
                | 
                42,256
                | 
                
 |  
              | 
                Depreciation and amortization
                | 
                2,572
                | 
                
 | 
                
                | 
                —
                | 
                
 |  
              | 
                Unearned revenue
                | 
                13,937
                | 
                
 | 
                
                | 
                12,010
                | 
                
 |  
              | 
                Other
                | 
                29,483
                | 
                
 | 
                
                | 
                25,454
                | 
                
 |  
              | 
                Gross deferred tax assets
                | 
                393,771
                | 
                
 | 
                
                | 
                392,371
                | 
                
 |  
              | 
                Valuation allowance
                | 
                (76,328
                | 
                )
                | 
                
                | 
                (57097
                | 
                )
                |  
              | 
                Net deferred tax assets
                | 
                $
                | 
                317,443
                | 
                
 | 
                
                | 
                $
                | 
                335,274
                | 
                
 |  
              | 
                Deferred tax liabilities:
                | 
                
                | 
                
                | 
                
                |  
              | 
                Unremitted earnings of foreign subsidiaries not permanently reinvested
                | 
                $
                | 
                (17,334
                | 
                )
                | 
                
                | 
                $
                | 
                (20,636
                | 
                )
                |  
              | 
                Depreciation and amortization
                | 
                —
                | 
                
 | 
                
                | 
                (1,863
                | 
                )
                |  
              | 
                Deferred profit
                | 
                (16,358
                | 
                )
                | 
                
                | 
                (10,351
                | 
                )
                |  
              | 
                Unrealized gain on investments
                | 
                (1,168
                | 
                )
                | 
                
                | 
                (572
                | 
                )
                |  
              | 
                Total deferred tax liabilities
                | 
                (34,860
                | 
                )
                | 
                
                | 
                (33,422
                | 
                )
                |  
              | 
                Total net deferred tax assets
                | 
                $
                | 
                282,583
                | 
                
 | 
                
                | 
                $
                | 
                301,852
                | 
                
 |  | 
      
       | 的时间表Effective Income Tax Rate Reconciliation | 
         
          The reconciliation of the United States federal statutory income tax rate to KLA-Tencor’s effective income tax rate is as follows:
          
          
           
            
             
              |  |  
              |  |  |  |  |  |  |  |  |  |  
              | 
                
                | 
                Year ended June 30,
                |  
              | 
                
                | 
                2014
                | 
                
                | 
                2013
                | 
                
                | 
                2012
                |  
              | 
                Federal statutory rate
                | 
                35.0
                | 
                %
                | 
                
                | 
                35.0
                | 
                %
                | 
                
                | 
                35.0
                | 
                %
                |  
              | 
                State income taxes, net of federal benefit
                | 
                0.7
                | 
                %
                | 
                
                | 
                0.3
                | 
                %
                | 
                
                | 
                0.4
                | 
                %
                |  
              | 
                Effect of foreign operations taxed at various rates
                | 
                (11.5
                | 
                )%
                | 
                
                | 
                (9.6
                | 
                )%
                | 
                
                | 
                (9.9
                | 
                )%
                |  
              | 
                Research and development tax credit
                | 
                (1.5
                | 
                )%
                | 
                
                | 
                (3.1
                | 
                )%
                | 
                
                | 
                (1.1
                | 
                )%
                |  
              | 
                Net change in tax reserves
                | 
                0.3
                | 
                %
                | 
                
                | 
                1.7
                | 
                %
                | 
                
                | 
                (2.8
                | 
                )%
                |  
              | 
                Domestic manufacturing benefit
                | 
                (1.4
                | 
                )%
                | 
                
                | 
                (1.6
                | 
                )%
                | 
                
                | 
                (0.7
                | 
                )%
                |  
              | 
                Effect of stock-based compensation
                | 
                0.4
                | 
                %
                | 
                
                | 
                (0.3
                | 
                )%
                | 
                
                | 
                1.3
                | 
                %
                |  
              | 
                Other
                | 
                (1.3
                | 
                )%
                | 
                
                | 
                (1.0
                | 
                )%
                | 
                
                | 
                0.2
                | 
                %
                |  
              | 
                Effective income tax rate
                | 
                20.7
                | 
                %
                | 
                
                | 
                21.4
                | 
                %
                | 
                
                | 
                22.4
                | 
                %
                |  | 
      
       | Summary of Income Tax Contingencies | 
         
          A reconciliation of gross unrecognized tax benefits is as follows:
          
          
          
           
            
             
              |  |  
              |  |  |  |  |  |  |  |  |  |  |  |  |  
              | 
                
                | 
                Year ended June 30,
                |  
              | 
                (In thousands)
                | 
                2014
                | 
                
                | 
                2013
                | 
                
                | 
                2012
                |  
              | 
                Unrecognized tax benefits at the beginning of the period
                | 
                $
                | 
                59,494
                | 
                
 | 
                
                | 
                $
                | 
                50,839
                | 
                
 | 
                
                | 
                $
                | 
                78,337
                | 
                
 |  
              | 
                Increases for tax positions taken in prior years
                | 
                551
                | 
                
 | 
                
                | 
                2,701
                | 
                
 | 
                
                | 
                4,172
                | 
                
 |  
              | 
                Decreases for tax positions taken in prior years
                | 
                (764
                | 
                )
                | 
                
                | 
                (905
                | 
                )
                | 
                
                | 
                (1,002
                | 
                )
                |  
              | 
                Increases for tax positions taken in current year
                | 
                11585年
                | 
                
 | 
                
                | 
                12,709
                | 
                
 | 
                
                | 
                15,663
                | 
                
 |  
              | 
                Decreases for settlements with taxing authorities
                | 
                (3,601
                | 
                )
                | 
                
                | 
                (3,907
                | 
                )
                | 
                
                | 
                (43,464
                | 
                )
                |  
              | 
                Decreases for lapsing of statutes of limitations
                | 
                (7,690
                | 
                )
                | 
                
                | 
                (1,943
                | 
                )
                | 
                
                | 
                (2,867
                | 
                )
                |  
              | 
                Unrecognized tax benefits at the end of the period
                | 
                $
                | 
                59,575
                | 
                
 | 
                
                | 
                $
                | 
                59,494
                | 
                
 | 
                
                | 
                $
                | 
                50,839
                | 
                
 |  |