Compensation - Compensation Expense Related to Limited Partnership Units that were Not Redeemed (Details) - NEWMARK Group Inc - Limited Partnership Units - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Share-based Compensation Arrangement by Share-based Payment Award
Post-termination payout	$ 3,104	$ 3,369	$ 6,386	$ 8,230
Stated vesting schedule	4,065	4,065	8,130	6,775
Limited partnership units amortization	$ 7,169	$ 7,434	$ 14,516	$ 15,005