Schedule I - Parent Company Only - Subsequent Events (Detail) - Subsequent Event shares in Millions	Feb. 17, 2021 $ / shares shares
Subsequent Event
Number of shares authorized to be repurchased (in shares) | shares	400
Dividends declared per share of common stock (dollars per share) | $ / shares	$ 0.01
NEWMARK Group Inc Parent
Subsequent Event
Number of shares authorized to be repurchased (in shares) | shares	400
Dividends declared per share of common stock (dollars per share) | $ / shares	$ 0.01