Name:	laz_AmountOfCashSavingsInIncomeOrFranchiseTaxThatWouldBeRealizedAsResultOfIncreasesInTaxBasisAndCertainOtherTaxBenefitsRelatedToAmendedAndRestatedTaxReceivableAgreement
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Data Type:	num:percentItemType
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Cash tax saving that may arise from tax benefits attributable to payments under the amended and restated tax receivable agreement.

No definition available.

Name:	laz_CashTaxSavingThatMayAriseFromTaxBenefitsAttributableToPaymentsUnderAmendedAndRestatedTaxReceivableAgreement
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Data Type:	num:percentItemType
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Payable pursuant to the tax receivable agreement.

No definition available.

Name:	laz_PayablePursuantToTaxReceivableAgreement
Namespace Prefix:	laz_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Amount of cash outflow made in accordance with the tax receivable agreement obligation.

No definition available.

Name:	laz_PaymentsForTaxReceivableAgreementObligation
Namespace Prefix:	laz_
Data Type:	xbrli:monetaryItemType
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Period Type:	duration

Reduction in payable pursuant to tax receivable agreement.

No definition available.

Name:	laz_ReductionInPayablePursuantToTaxReceivableAgreement
Namespace Prefix:	laz_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

For an unclassified balance sheet, the amount of fees and other revenue, excluding investment income receivable, earned but not yet received, which were recognized in conformity with revenue recognition criteria based on estimates or specific contractual terms.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.3)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Name:	us-gaap_AccruedFeesAndOtherRevenueReceivable
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Amount of fixed fee revenue for the management of an investment fund portfolio. Excludes investment advisory, distribution and servicing, and performance fees.

No definition available.

Name:	us-gaap_AssetManagementFees1
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32687-109319

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB TOPIC 6.I)
-URI http://asc.fasb.org/extlink&oid=34349781&loc=d3e330036-122817

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32698-109319

Name:	us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
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.