Debt Instrument, Additional Margin Interest Rate

No definition available.

Name:	lcii_DebtInstrumentAdditionalMarginInterestRate
Namespace Prefix:	lcii_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Letter Of Credit

+ References

No definition available.

+ Details

Name:	lcii_LetterOfCredit
Namespace Prefix:	lcii_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Line of Credit Facility, Additional Maximum Borrowing Capacity Upon Approval

+ References

No definition available.

+ Details

Name:	lcii_LineofCreditFacilityAdditionalMaximumBorrowingCapacityUponApproval
Namespace Prefix:	lcii_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28551-108399

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

+ Details

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

- Definition

The average effective interest rate during the reporting period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28551-108399

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Definition

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Definition

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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

- 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.

+ References

No definition available.

+ Details

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

- 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.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)(3)
-URI http://asc.fasb.org/extlink&oid=109500613&loc=SL6031897-161870

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Definition

Amount after unamortized (discount) premium and debt issuance costs of long-term debt classified as noncurrent and excluding amounts to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_MediumTermNotesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentRedemptionPeriodAxis=us-gaap_DebtInstrumentRedemptionPeriodOneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentRedemptionPeriodAxis=us-gaap_DebtInstrumentRedemptionPeriodTwoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LineOfCreditFacilityAxis=lcii_JpmorganChaseBankAndWellsFargoBankMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_LineOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_PrimeRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LineOfCreditFacilityAxis=lcii_PrudentialInvestmentManagementIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LineOfCreditFacilityAxis=lcii_JPMorganChaseBankN.A.WellsFargoBankN.A.BankofAmericaN.A.and1stSourceBankMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	lcii_BorrowingInterestRateOptionsAxis=lcii_OptionOneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_LondonInterbankOfferedRateLIBORMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_FederalFundsEffectiveSwapRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	lcii_BorrowingInterestRateOptionsAxis=lcii_OptionTwoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Long-Term Indebtedness (Narrative) (Details) € in Millions						3 Months Ended
Long-Term Indebtedness (Narrative) (Details) € in Millions	Dec. 19, 2019 USD ($)	Mar. 29, 2019 USD ($)	Dec. 14, 2018 USD ($)	Apr. 27, 2016 USD ($)	Mar. 20, 2015 USD ($)	Mar. 31, 2020 USD ($)	Mar. 31, 2020 EUR (€)	Dec. 31, 2019 USD ($)	Nov. 11, 2019 USD ($)	Feb. 24, 2014 USD ($)
Line of Credit Facility
Long-term indebtedness						$ 750,519,000		$ 612,906,000
Borrowings						768,818,000		$ 630,789,000
Remaining availability under the facilities						341,700,000
Medium-term Notes [Member]
Line of Credit Facility
Debt Instrument, Face Amount	$ 300,000,000.0
Medium-term Notes [Member] \| Period one
Line of Credit Facility
Debt term	2 years
Debt Instrument, Interest Rate, Stated Percentage	1.25%
Medium-term Notes [Member] \| Period two
Line of Credit Facility
Debt Instrument, Interest Rate, Stated Percentage	1.875%
JPMorgan Chase Bank And Wells Fargo Bank \| Line of Credit
Line of Credit Facility
Maximum borrowings under line of credit				$ 325,000,000.0
Long-term indebtedness			$ 250,000,000.0
Borrowings						138,300,000	€ 126.0
Letter of credit						2,700,000
Remaining availability under the facilities						$ 191,700,000
JPMorgan Chase Bank And Wells Fargo Bank \| Line of Credit \| Prime Rate
Line of Credit Facility
Basis spread on variable rate						1.00%
JPMorgan Chase Bank And Wells Fargo Bank \| Line of Credit \| Prime Rate \| Minimum
Line of Credit Facility
Basis spread on variable rate						1.00%
Prudential Investment Management Inc \| Line of Credit
Line of Credit Facility
Long-term indebtedness		$ 50,000,000.0			$ 50,000,000.0				$ 200,000,000.0
Remaining availability under the facilities										$ 150,000,000.0
Debt term		3 years			5 years
Interest rate during period		3.80%			3.35%
JPMorgan Chase Bank, N.A., Wells Fargo Bank, N.A., Bank of America, N.A., and 1st Source Bank \| Line of Credit
Line of Credit Facility
Maximum borrowings under line of credit	$ 900,000,000.0		$ 600,000,000.0
Line of Credit Facility, Additional Maximum Borrowing Capacity Upon Approval	$ 300,000,000.0
Option One \| JPMorgan Chase Bank, N.A., Wells Fargo Bank, N.A., Bank of America, N.A., and 1st Source Bank \| Line of Credit \| LIBOR \| Minimum
Line of Credit Facility
Debt instrument, additional margin interest rate				0.00%		0.40%
Option One \| JPMorgan Chase Bank, N.A., Wells Fargo Bank, N.A., Bank of America, N.A., and 1st Source Bank \| Line of Credit \| LIBOR \| Maximum
Line of Credit Facility
Debt instrument, additional margin interest rate			0.625%
Option One \| JPMorgan Chase Bank, N.A., Wells Fargo Bank, N.A., Bank of America, N.A., and 1st Source Bank \| Line of Credit \| Federal Funds Effective Rate
Line of Credit Facility
Basis spread on variable rate			0.50%
Option Two \| JPMorgan Chase Bank, N.A., Wells Fargo Bank, N.A., Bank of America, N.A., and 1st Source Bank \| Line of Credit \| LIBOR \| Maximum
Line of Credit Facility
Basis spread on variable rate			1.625%