Lines of Credit and Financing Arrangements (Details Textual 2) (Line of Credit [Member], USD $)	12 Months Ended
Dec. 31, 2014
Line of Credit [Member]
Line of Credit Facility [Line Items]
Minimum amount of principal or interest due on indebtedness or receivable securitization	$ 75,000,000

Minimum amount of principal or interest due on indebtedness or receivable securitization.

No definition available.

Name:	lii_MinimumAmountOfPrincipalOrInterestDueOnIndebtednessOrReceivableSecuritization
Namespace Prefix:	lii_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration