Compensation - Schedule of Limited Partnership Units with a Post-Termination Payout (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2026	Dec. 31, 2025
BGC Holdings, L.P.
Share-based Compensation Arrangement by Share-based Payment Award
Notional Value	$ 138,557	$ 153,976
Estimated fair value of the post-termination payout	$ 54,896	$ 61,406
Newmark Holdings Units
Share-based Compensation Arrangement by Share-based Payment Award
Outstanding limited partnership units (in shares)	13,688,470	15,082,749
Outstanding limited partnership units - unvested (in shares)	3,465,843	3,959,532