Compensation - Limited Partnership Units with a Post-Termination Payout (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2023	Dec. 31, 2022
BGC Holdings, L.P.
Share-based Compensation Arrangement by Share-based Payment Award
Notional value	$ 157,222	$ 144,045
Estimated fair value of the post-termination payout	$ 49,771	$ 42,706
Outstanding limited partnership units (in shares)	0	44,928
NEWMARK Group Inc Parent
Share-based Compensation Arrangement by Share-based Payment Award
Outstanding limited partnership units (in shares)	15,944,838	14,277,213
Outstanding limited partnership units - unvested (in dollars per share)	1,536,784	2,155,668