Quarterly report pursuant to Section 13 or 15(d)

Stock Repurchase Program (Details)

v2.4.1.9
Stock Repurchase Program (Details) (USD $)
In Thousands, except Share data, unless otherwise specified
 0 Months Ended 3 Months Ended 6 Months Ended
Oct. 23, 2014
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2014
Dec. 31, 2013
Jul. 08, 2014
Equity, Class of Treasury Stock [Line Items]            
Increase in authorized shares to be repurchased           13,000,000us-gaap_StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased
Number of additional shares authorized to be repurchased 3,600,000klac_StockRepurchaseProgramNumberofAdditionalSharesAuthorized          
Authorized shares to be repurchased   14,800,000us-gaap_StockRepurchaseProgramRemainingNumberOfSharesAuthorizedToBeRepurchased   14,800,000us-gaap_StockRepurchaseProgramRemainingNumberOfSharesAuthorizedToBeRepurchased    
Number of shares of common stock repurchased   2,120,000us-gaap_TreasuryStockSharesAcquired 959,000us-gaap_TreasuryStockSharesAcquired 3,862,000us-gaap_TreasuryStockSharesAcquired 1,997,000us-gaap_TreasuryStockSharesAcquired  
Total cost of repurchases   $ 148,266us-gaap_TreasuryStockValueAcquiredCostMethod $ 60,302us-gaap_TreasuryStockValueAcquiredCostMethod $ 278,949us-gaap_TreasuryStockValueAcquiredCostMethod $ 120,806us-gaap_TreasuryStockValueAcquiredCostMethod  
Other Current Liabilities            
Equity, Class of Treasury Stock [Line Items]            
Number of shares of common stock repurchased   176,123us-gaap_TreasuryStockSharesAcquired
/ us-gaap_BalanceSheetLocationAxis
= us-gaap_OtherCurrentLiabilitiesMember 		       
Total cost of repurchases   $ 12,600us-gaap_TreasuryStockValueAcquiredCostMethod
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= us-gaap_OtherCurrentLiabilitiesMember