Defined benefit plan, target allocation, percentage of plan assets invested.

No definition available.

Name:	laz_DefinedBenefitPlanTargetAllocationPercentageOfPlanAssetsInvested
Namespace Prefix:	laz_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of equity funds that are invested in funds that are managed by the company.

+ References

No definition available.

+ Details

Name:	laz_EquityFundsThatInvestedInFundsManagedByCompany
Namespace Prefix:	laz_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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.

+ References

No definition available.

+ Details

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

- Definition

Amount of contribution expected to be received by defined benefit plan from employer in next fiscal year following current fiscal year.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (g)
-URI https://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 55
-Paragraph 18
-URI https://asc.fasb.org/extlink&oid=123450688&loc=d3e4587-114921

+ Details

Name:	us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of discretionary contributions made by an employer to a defined contribution plan.

+ References

No definition available.

+ Details

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

- Details

Name:	us-gaap_RetirementPlanSponsorLocationAxis=country_US
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=laz_DebtFundsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_DefinedBenefitPlanCashMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ValuationTechniqueAxis=laz_NetAssetValueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_EquityFundsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RetirementPlanSponsorLocationAxis=us-gaap_ForeignPlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=laz_FairValueInputsLevel1AndLevel2Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=laz_EquitiesAndEquityFundsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=laz_DebtAndDebtFundsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=laz_CashAndAlternativeInvestmentFundsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BalanceSheetLocationAxis=us-gaap_OtherInvestmentsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Employee Benefit Plans - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Defined Benefit Plan Disclosure [Line Items]
Equity funds that are invested in funds managed by the company	$ 54,810	$ 68,529
Contributions to employer sponsored defined contribution plans	19,692	$ 17,864	$ 16,736
Unites States [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected contribution related to the pension plans for fiscal 2023	$ 1,000
Unites States [Member] \| Level 1 [Member] \| Debt Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of plan assets invested	42.00%	46.00%
Unites States [Member] \| Level 1 [Member] \| Cash [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of plan assets invested	1.00%
Unites States [Member] \| Level 1 [Member] \| NAV [Member] \| Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of plan assets invested	57.00%	54.00%
Non-U.S. Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected contribution related to the pension plans for fiscal 2023	$ 3,000
Non-U.S. Pension Plans [Member] \| Level 1 and Level 2 [Member] \| Equities And Equity Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of plan assets invested	25.00%	32.00%
Non-U.S. Pension Plans [Member] \| Level 1 and Level 2 [Member] \| NAV [Member] \| Debt and Debt Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of plan assets invested	66.00%	64.00%
Non-U.S. Pension Plans [Member] \| Level 1 and Level 2 [Member] \| NAV [Member] \| Cash And Alternative Investment Funds [Member] \| Other Investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Percentage of plan assets invested	9.00%	4.00%