Consideration Transferred to Acquire Novellus (Parenthetical) (Detail) (Novellus Systems Incorporated)	Jun. 04, 2012
Novellus Systems Incorporated
Business Acquisition, Equity Interests Issued or Issuable [Line Items]
Exchange ratio	1.125

The ratio by which Novellus Systems Inc. shares were converted to Lam Research Inc. shares as a result of the acquisition of Novellus.

No definition available.

Name:	lrcx_ConvertibleSharesExchangeRatio
Namespace Prefix:	lrcx_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant