Earnings Per Share and Weighted-Average Shares Outstanding - Schedule of Fully Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Fully diluted earnings per share:
Net income (loss) available to common stockholders	$ 61,234	$ 42,575	$ 83,275
Allocations of net income to limited partnership interests in Newmark Holdings, net of tax	0	0	27,128
Net income (loss) for fully diluted shares	$ 61,234	$ 42,575	$ 110,403
Weighted-average shares:
Common stock outstanding (in shares)	172,179	173,475	180,337
Partnership units (in shares)	0	0	59,944
RSUs (Treasury stock method) (in shares)	5,110	2,413	3,255
Newmark exchange shares (in shares)	402	494	1,641
Fully diluted weighted-average shares of common stock outstanding (in shares)	177,691	176,382	245,177
Fully diluted earnings per share (in dollars per share)	$ 0.34	$ 0.24	$ 0.45