Name:	lii_SharebasedCompensationArrangementbySharebasedPaymentAwardNonOptionEquityInstrumentsExercisableIntrinsicValue
Namespace Prefix:	lii_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Exercisable, Number

No definition available.

Name:	lii_SharebasedCompensationArrangementbySharebasedPaymentAwardNonOptionEquityInstrumentsExercisableNumber
Namespace Prefix:	lii_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding, Intrinsic Value

No definition available.

Name:	lii_SharebasedCompensationArrangementbySharebasedPaymentAwardNonOptionEquityInstrumentsOutstandingIntrinsicValue
Namespace Prefix:	lii_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Share-based Compensation, Shares Authorized under Non-Option Equity Instrument Plans, Exercise Price Range, Lower Range Limit

No definition available.

Name:	lii_SharebasedCompensationSharesAuthorizedunderNonOptionEquityInstrumentPlansExercisePriceRangeLowerRangeLimit
Namespace Prefix:	lii_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	duration

Share-based Compensation, Shares Authorized under Non-Option Equity Instrument Plans, Exercise Price Range, Upper Range Limit

No definition available.

Name:	lii_SharebasedCompensationSharesAuthorizedunderNonOptionEquityInstrumentPlansExercisePriceRangeUpperRangeLimit
Namespace Prefix:	lii_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	duration

Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Non-Option Equity Instruments, Weighted Average Remaining Contractual Term

No definition available.

Name:	lii_SharebasedCompensationSharesAuthorizedunderStockOptionPlansExercisePriceRangeExercisableNonOptionEquityInstrumentsWeightedAverageRemainingContractualTerm
Namespace Prefix:	lii_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Non-Option Equity Instruments, Weighted Average Remaining Contractual Term

No definition available.

Name:	lii_SharebasedCompensationSharesAuthorizedunderStockOptionPlansExercisePriceRangeOutstandingNonOptionEquityInstrumentsWeightedAverageRemainingContractualTerm
Namespace Prefix:	lii_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

Name:	us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Number of equity instruments other than options outstanding, including both vested and non-vested instruments.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(ii)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(i)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingNumber
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

Name:	us-gaap_AwardTypeAxis=us-gaap_StockAppreciationRightsSARSMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis=lii_ExercisePriceRange1Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis=lii_ExercisePriceRange2Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: