Loss Per Share (Details Textual)	3 Months Ended
Mar. 31, 2012	Mar. 31, 2011
Loss Per Share (Textual) [Abstract]
Diluted loss per share	636,860	1,128,847

Potentially dilutive securities excluded from computation of earnings per share amount.

No definition available.

Name:	lii_PotentiallyDilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
Namespace Prefix:	lii_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration