Compensation - Compensation Expense Related to Issuance of Common Stock and Grants of Exchangeability (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Share-Based Payment Arrangement [Abstract]
Issuance of common stock and exchangeability expenses	$ 36,953	$ 11,852	$ 89,232	$ 47,958

Common Stock, Exchangeability Granted, Issued, Expense

No definition available.

Name:	nmrk_CommonStockExchangeabilityGrantedIssuedExpense
Namespace Prefix:	nmrk_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration