Earnings Per Share and Weighted-Average Shares Outstanding - Calculation of Basic Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		12 Months Ended
		Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Basic earnings per share
Net income available to common stockholders	[1]	$ 83,275	$ 744,528	$ 70,281
Basic weighted-average shares of common stock outstanding (in shares)		180,337	190,179	179,106
Basic earnings per share (in usd per share)		$ 0.46	$ 3.91	$ 0.39
NEWMARK Group Inc Parent
Earnings Per Share
Reduction for dividends on preferred stock or units			$ 6,200	$ 9,800

[1] Includes a reduction for dividends on EPUs in the amount of $6.2 million and $9.8 million for the years ended December 31, 2021 and 2020, respectively (see Note 1 — “Organization and Basis of Presentation”).