Incentive Plans - Summary of Activity Relating to PIPRs (Details) - $ / shares	12 Months Ended
Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Ordinary PIPRs
Units
Units beginning balance (in shares)	2,640,769
Units granted (in shares)	1,368,964
Units forfeited (in shares)	(76,737)
Units settled (in shares)	(601,433)
Units ending balance (in shares)	3,331,563	2,640,769
Weighted Average Grant Date Fair Value
Weighted average grant date fair value, beginning balance (in usd per share)	$ 36.19
Weighted average grant date fair value, granted (in usd per share)	38.26	$ 34.50	$ 32.95
Weighted average grant date fair value, forfeited (in usd per share)	36.13
Weighted average grant date fair value, settled (in usd per share)	43.23
Weighted average grant date fair value, ending balance (in usd per share)	$ 35.77	$ 36.19
P-PIPRs
Units
Units beginning balance (in shares)	1,958,829
Units granted (in shares)	0
Units forfeited (in shares)	0
Units settled (in shares)	(995,169)
Units ending balance (in shares)	963,660	1,958,829
Weighted Average Grant Date Fair Value
Weighted average grant date fair value, beginning balance (in usd per share)	$ 41.12
Weighted average grant date fair value, granted (in usd per share)	0		$ 35.44
Weighted average grant date fair value, forfeited (in usd per share)	0
Weighted average grant date fair value, settled (in usd per share)	46.63
Weighted average grant date fair value, ending balance (in usd per share)	$ 35.44	$ 41.12
SP-PIPRs
Units
Units beginning balance (in shares)	2,250,000
Units granted (in shares)	0
Units forfeited (in shares)	0
Units settled (in shares)	0
Units ending balance (in shares)	2,250,000	2,250,000
Weighted Average Grant Date Fair Value
Weighted average grant date fair value, beginning balance (in usd per share)	$ 15.06
Weighted average grant date fair value, granted (in usd per share)	0	$ 15.06
Weighted average grant date fair value, forfeited (in usd per share)	0
Weighted average grant date fair value, settled (in usd per share)	0
Weighted average grant date fair value, ending balance (in usd per share)	$ 15.06	$ 15.06

The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event.

+ References

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(i)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(ii)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480429/718-10-50-2

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

+ Details

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

- Definition

Per share or unit weighted-average fair value of nonvested award under share-based payment arrangement. Excludes share and unit options.

+ References

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	instant

- References

No definition available.

+ Details

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

- Definition

The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

+ References

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

+ References

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_AwardTypeAxis=laz_OrdinaryPIPRsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardTypeAxis=laz_PerformancePIPRsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardTypeAxis=laz_StockPricePIPRsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: