Lines of Credit and Financing Arrangements (Details 4)	Dec. 31, 2012	Dec. 31, 2011
Summary of weighted average borrowing rate facility
Weighted average borrowing rate	1.46%	1.53%

Line of credit facility weighted average borrowing rate.

No definition available.

Name:	lii_LineOfCreditFacilityWeightedAverageBorrowingRate
Namespace Prefix:	lii_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant