Debt Instrument, Covenant, Net Leverage Ratio

No definition available.

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- Definition

Debt Instrument, Covenant, Net Leverage Ratio Following Material Acquisition

+ References

No definition available.

+ Details

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- Definition

Debt Instrument, Extension Term

+ References

No definition available.

+ Details

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- Definition

Debt Instrument, Number Of Extension Options

+ References

No definition available.

+ Details

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Period Type:	instant

- Definition

Line of Credit Facility, Accordion Feature, Increase Limit

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

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

+ References

No definition available.

+ Details

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

- Definition

Revolving credit facility committed to stand by letters of credit.

+ References

No definition available.

+ Details

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Namespace Prefix:	lii_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

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+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

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- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

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+ Details

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Balance Type:	credit
Period Type:	instant

- Definition

Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility.

+ References

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Balance Type:	credit
Period Type:	instant

- Definition

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.

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- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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- Details

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Period Type:

- Details

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- Details

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- Details

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- Details

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Lines of Credit and Financing Arrangements (Domestic Credit Facility) (Details)	1 Months Ended	6 Months Ended
	Aug. 31, 2023 USD ($)	Jun. 30, 2025 USD ($) option	May 09, 2025 USD ($)	May 08, 2025 USD ($)	Jul. 31, 2021	Jul. 30, 2020 USD ($)
Revolving Credit Facility
Line of Credit Facility [Line Items]
Maximum borrowing capacity			$ 1,000,000,000.0	$ 1,100,000,000
Line of Credit Facility, Accordion Feature, Increase Limit			$ 350,000,000
Subfacility for Swingline Loans
Line of Credit Facility [Line Items]
Maximum borrowing capacity		$ 65,000,000
Debt instrument, number of extension options \| option		2
Debt Instrument, Extension Term		1 year
Senior Notes [Member]
Line of Credit Facility [Line Items]
Minimum principal amount accelerated	$ 75,000,000.0	$ 75,000,000.0
Revolving Credit Facility
Line of Credit Facility [Line Items]
Outstanding borrowings		0
Committed standby letters of credit		1,700,000
Available for future borrowings		$ 969,300,000
Debt instrument, covenant, net leverage ratio					3.50
Debt instrument, covenant, net leverage ratio following material acquisition					4.00
2025 Notes [Member] \| Senior Notes [Member]
Line of Credit Facility [Line Items]
Face amount of debt						$ 300,000,000
Debt instrument, interest rate, stated percentage						1.35%
2027 Notes [Member] \| Senior Notes [Member]
Line of Credit Facility [Line Items]
Face amount of debt						$ 300,000,000
Debt instrument, interest rate, stated percentage						1.70%