Number of operating segments. An operating segment is a component of an enterprise: (a) that engages in business activities from which it may earn revenues and incur expenses (including revenues and expenses relating to transactions with other components of the same enterprise), (b) whose operating results are regularly reviewed by the enterprise's chief operating decision maker to make decisions about resources to be allocated to the segment and assess its performance, and (c) for which discrete financial information is available. An operating segment may engage in business activities for which it has yet to earn revenues, for example, start-up operations may be operating segments before earning revenues.

No definition available.

Name:	us-gaap_NumberOfOperatingSegments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

Organization and Basis of Presentation - Additional Information (Detail) - Segment		12 Months Ended
	Feb. 04, 2019	Dec. 31, 2019	Dec. 31, 2018
Organization And Basis Of Presentation [Line Items]
Governing operating agreement, date	Feb. 04, 2019
Number of business segments		2
Lazard Group LLC [Member]
Organization And Basis Of Presentation [Line Items]
Percentage of common membership interests held		100.00%	100.00%