XML 90 R79.htm IDEA: XBRL DOCUMENT v3.21.1

Loans Held for Sale, at Fair Value - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Accounts and Financing Receivables, Held-for-Sale, Not Part of Disposal Group, after Valuation Allowance [Abstract]
Maximum period of loans held for sale sold (in days)	45 days
Financing receivable, nonaccrual	$ 0	$ 0

X

- Definition

Maximum period of loans held for sale sold.

+ References

No definition available.

+ Details

Name:	nmrk_MaximumPeriodOfLoansHeldForSaleSold
Namespace Prefix:	nmrk_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Amount of financing receivable on nonaccrual status.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 7
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5111-111524

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 16
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121599337&loc=SL82919258-210447

+ Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- References

No definition available.

+ Details

Name:	us-gaap_ReceivablesHeldForSaleNetAmountAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration