Incentive Plans - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands			1 Months Ended	12 Months Ended
	Apr. 29, 2021	Apr. 24, 2018	Feb. 28, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Subsequent Event [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Deferred incentive compensation awards			$ 390,000
Award vesting description			RSUs, restricted common stock and LFI granted generally provide for one-third vesting on the second anniversary of the grant date and the remaining two-thirds vesting on the third anniversary of the grant date, so long as applicable conditions have been satisfied. PRSUs and the profits interest participation rights granted generally provide for vesting on the third anniversary of the grant date, so long as applicable conditions have been satisfied.
Lazard Fund Interests [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense, years				9 months 18 days
Non-Executive [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of annual compensation received by directors in the form of DSUs				55.00%
RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock conversion basis				one-for-one
Grant date fair value, amortized periods				generally, one-third after two years and the remaining two-thirds after the third year
Number of dividend participation rights issued				384,423
Charges to retained earnings, net of estimated forfeitures				$ 15,948
Weighted-average grant date fair value of awards granted				$ 43.38	$ 42.60	$ 38.65
Unrecognized compensation expense				$ 90,862
Unrecognized compensation expense, years				9 months 18 days
DSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average grant date fair value of awards granted				$ 46.75	28.49	32.38
DSUs [Member] | Non-Executive [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual compensation received for service				30,764
Units granted under the directors deferred unit plan				14,501
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Charges to retained earnings, net of estimated forfeitures				$ 1,524
Weighted-average grant date fair value of awards granted				$ 43.80	42.89	35.32
Unrecognized compensation expense				$ 13,780
Unrecognized compensation expense, years				10 months 24 days
Dividend participation rights				34,208
PRSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average grant date fair value of awards granted				$ 46.63	50.74	38.09
Unrecognized compensation expense				$ 1,618
Unrecognized compensation expense, years				1 year 1 month 6 days
Descriptions of vesting period				PRSUs will vest on a single date approximately three years following the date of the grant
Vesting period				3 years
PRSUs target share distribution for Class A common stock, description				The target number of shares of common stock subject to each PRSU is one; however, based on the achievement of the performance criteria, the number of shares of common stock that may be received in connection with each PRSU generally can range from zero to two times the target number for awards granted prior to February 2021. For awards granted in February 2021, based on both the performance-based and market-based criteria, the number of shares of common stock can range from zero to 2.4 times the target number.
Profits Interest Participation Rights [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock conversion basis				one-for-one
Weighted-average grant date fair value of awards granted				$ 44.73	$ 42.89	$ 38.65
Unrecognized compensation expense				$ 23,462
Unrecognized compensation expense, years				9 months 18 days
Descriptions of vesting period				Profits interest participation rights generally provide for vesting approximately three years following the grant date
Vesting period				3 years
PRSUs target share distribution for Class A common stock, description				The target number of shares of common stock subject to each PRPU is one. Based on the achievement of performance criteria, as determined by the Compensation Committee, the number of shares of common stock that may be received in connection with the PRPU awards granted in February 2019 and February 2020 will range from zero to two times the target number. For the PRPU awards granted in February 2021, subject to both performance-based and incremental market-based criteria, the number of shares will range from zero to 2.4 times the target number.
Percentage of target number of shares subject to the applicable units no longer subject to forfeiture due to threshold level of performance being achieved				25.00%
Common Stock [Member] | RSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Withholding taxes in lieu of share delivery				1,374,578
Delivery of common stock associated with stock awards				2,738,287
Common Stock [Member] | Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Withholding taxes in lieu of share delivery				205,007
Delivery of common stock associated with stock awards				418,474
Common Stock [Member] | PRSUs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Withholding taxes in lieu of share delivery				100,882
Delivery of common stock associated with stock awards				446,077
2018 Equity Incentive Plan [Member] | Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized pertaining to share based compensation arrangements		30,000,000
Share-based compensation arrangement by share-based payment award, number of additional shares authorized	20,000,000
Awarded Under 2008 Plan [Member] | Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of outstanding Class A common stock available under the plan		30.00%
Compensation plan expiration period		Apr. 24, 2018
2005 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation plan expiration period				second quarter of 2015
2005 Equity Incentive Plan [Member] | Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized pertaining to share based compensation arrangements				25,000,000