Name:	lii_EmployeeBenefitPlansTextualAbstract
Namespace Prefix:	lii_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Percentage of Fair Value of Plan Assets by Pension Plans.

+ References

No definition available.

+ Details

Name:	lii_PercentageOfFairValueOfPlanAssetsByPensionPlans
Namespace Prefix:	lii_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of Fair Value of Plan Assets Held.

+ References

No definition available.

+ Details

Name:	lii_PercentageOfFairValueOfPlanAssetsHeld
Namespace Prefix:	lii_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of fixed income invest in inflation indexed bonds.

+ References

No definition available.

+ Details

Name:	lii_PercentageOfFixedIncomeInvestInInflationIndexedBonds
Namespace Prefix:	lii_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Cost of medical coverage payable by the participants.

+ References

No definition available.

+ Details

Name:	lii_PercentageOfMedicalCoverageCostPayableByParticipants
Namespace Prefix:	lii_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of Projected Benefit Obligation by Pension Plans.

+ References

No definition available.

+ Details

Name:	lii_PercentageOfProjectedBenefitObligationByPensionPlans
Namespace Prefix:	lii_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Weighted Average Maturity Period.

+ References

No definition available.

+ Details

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

- Definition

The amounts in accumulated other comprehensive income related to gains and losses that are not recognized immediately and are expected to be recognized as components of net periodic benefit cost over the next fiscal year that follows the most recent annual statement of financial position presented.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 132R

-Paragraph 5

-Subparagraph s

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 158

-Paragraph 7

-Subparagraph d

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (s)

-URI http://asc.fasb.org/extlink&oid=6962843&loc=d3e1928-114920

+ Details

Name:	us-gaap_DefinedBenefitPlanAmortizationOfNetGainsLosses
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The amounts in accumulated other comprehensive income related to prior service cost or credit expected to be recognized as components of net periodic benefit cost over the next fiscal year that follows the most recent annual statement of financial position presented.

+ References

+ Details

Name:	us-gaap_DefinedBenefitPlanAmortizationOfNetPriorServiceCostCredit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The interest rate used to adjust for the time value of money for the plan.

+ References

+ Details

Name:	us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

An assumption as to the rate of return on plan assets reflecting the average rate of earnings expected on the funds invested or to be invested to provide for the benefits included in the benefit obligation.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (k)(3)

-URI http://asc.fasb.org/extlink&oid=6962843&loc=d3e1928-114920

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 87

-Paragraph 264

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 132R

-Paragraph 5

-Subparagraph j

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Expected Long-Term Rate of Return on Plan Assets

-URI http://asc.fasb.org/extlink&oid=6512013

-Topic 715

-SubTopic 30

+ Details

Name:	us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

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

- Definition

The carrying amount as of the balance sheet date of the obligations recognized for the various benefits provided to former or inactive employees, their beneficiaries, and covered dependents after employment but before retirement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 112

-Paragraph 5

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 112

-Paragraph 4

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.15)

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 5

-Paragraph 9

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 112

-Paragraph 6

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 712

-SubTopic 10

-Section 25

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=6410138&loc=d3e79691-111665

Reference 7: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.15)

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 8: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 712

-SubTopic 10

-Section 25

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=6410138&loc=d3e79708-111665

+ Details

Name:	us-gaap_PostemploymentBenefitsLiabilityCurrentAndNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Employee Benefit Plans (Details Textual) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Defined Benefit Plan Disclosure [Line Items]
Percentage of fixed income invest in inflation indexed bonds	80.00%
Employee Benefit Plans (Textual) [Abstract]
Percentage of medical coverage cost payable by the participants	100.00%
Percentage of long-term rate of return on assets assumption	8.00%
Over funded amount included in Non Current Pension Liability	$ 0	0.1
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Estimated prior service (costs) credits	0.4
Estimated actuarial gains (losses)	9.2
Discount rate assumption	4.83%	5.45%
Employee Benefit Plans (Textual) [Abstract]
Percentage of long-term rate of return on assets assumption	8.00%	8.00%	8.25%
U.S.-based pension plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	89.20%
Plan assets	88.80%
Discount rate assumption	4.85%
Components of fair value in our plan assets		90.00%
U.S.-based pension plans [Member] \| Fixed income [Member] \| Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average maturity period	20 years
U.S.-based pension plans [Member] \| Fixed income [Member] \| Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average maturity period	7 years
U.S. non-qualified pension plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate assumption	4.59%
Canadian Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Components of fair value in our plan assets		6.00%
United Kingdom Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Components of fair value in our plan assets		4.00%
United Kingdom Pension Plans [Member] \| Fixed income [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average maturity period	5 years
Other Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Estimated prior service (costs) credits	1.9
Estimated actuarial gains (losses)	$ 1.2
Discount rate assumption	4.64%	5.30%
Employee Benefit Plans (Textual) [Abstract]
Percentage of long-term rate of return on assets assumption	0.00%	0.00%	0.00%