RECEIVABLES AND ALLOWANCE FOR CREDIT LOSSES - Additional Information (Details) - USD ($) $ in Thousands	Jun. 30, 2025	Dec. 31, 2024
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivables	$ 108,982	$ 130,682
Carrying amount	528,455	539,956
Customer and Other Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Customer loans	$ 117,358	$ 82,985

Customer loans are related to collateralized lending activities, loans granted by bank to third parties. and clearing organization relating to unsettled securities transactions

No definition available.

+ Details

Name:	laz_CustomerLoans
Namespace Prefix:	laz_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Financing fee receivables represent those receivables that are paid on an installment basis and may or may not include an interest component

+ References

No definition available.

+ Details

Name:	laz_FinancingFeeReceivable
Namespace Prefix:	laz_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Other Fees And Customers And Other Receivables Not Discussed Elsewhere In The Note

+ References

No definition available.

+ Details

Name:	laz_OtherFeesAndCustomersAndOtherReceivablesNotDiscussedElsewhereInTheNote
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

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 310
-SubTopic 20
-Name Accounting Standards Codification
-Section 40
-Paragraph 7
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481628/310-20-40-7

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481990/310-10-45-2

+ Details

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

- Details

Name:	us-gaap_FinancialInstrumentAxis=laz_CustomerAndOtherReceivablesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: