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, 2025	Dec. 31, 2024	Dec. 31, 2023
Fully diluted earnings per share:
Net income (loss) available to common stockholders	$ 126,186	$ 61,234	$ 42,575
Allocations of net income to limited partnership interests in Newmark Holdings, net of tax	46,808	0	0
Net income (loss) for fully diluted shares	$ 172,994	$ 61,234	$ 42,575
Weighted-average shares:
Common stock outstanding (in shares)	178,456	172,179	173,475
Partnership units (in shares)	69,773	0	0
RSUs (Treasury stock method) (in shares)	4,871	5,110	2,413
Newmark exchange shares (in shares)	350	402	494
Fully diluted weighted-average shares of common stock outstanding (in shares)	253,450	177,691	176,382
Fully diluted earnings per share (in dollars per share)	$ 0.68	$ 0.34	$ 0.24