Limited partnership interest distribution ratio.

No definition available.

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- Definition

Percentage of Distributions of shares in spin-off

+ References

No definition available.

+ Details

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Namespace Prefix:	nmrk_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of units distributed for payment of a unit distribution to unit-holder of limited partnership (LP).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 272
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6373374&loc=d3e70434-108055

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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-Topic 272
-SubTopic 10
-Section 50
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=109237563&loc=d3e33749-111570

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 25
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=115929826&loc=d3e8813-108599

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.12)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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Balance Type:	debit
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of units or percentage investment held in the subsidiary by the limited liability company or limited partnership.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 320
-Section S99
-Paragraph 9
-URI http://asc.fasb.org/extlink&oid=50485924&loc=d3e611443-123010

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- Details

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- Details

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- Details

Name:	srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=nmrk_CFRealEstateFinanceHoldingsLimitedPartnershipMember
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Related Party Transactions - CF Real Estate Finance Holdings, LP and IPO and Spin-Off (Details) - USD ($) $ in Thousands, shares in Millions	Nov. 30, 2018	Mar. 31, 2020	Dec. 31, 2019	Sep. 08, 2017
Related Party Transaction [Line Items]
Equity method investment		$ 99,966	$ 99,966
Class B Common Stock
Related Party Transaction [Line Items]
Aggregate distribution of shares in spin-off (in shares)	21.3
Class A Common Stock
Related Party Transaction [Line Items]
Aggregate distribution of shares in spin-off (in shares)	131.9
BGC Partners Inc \| Class B Common Stock
Related Party Transaction [Line Items]
Exchange ratio (per share)	46.3895%
Cantor And CFGM \| Class B Common Stock
Related Party Transaction [Line Items]
Percentage of Distributions of shares in spin-off	100.00%
Cantor And CFGM \| BGC Partners Inc \| Class B Common Stock
Related Party Transaction [Line Items]
Percentage of common shares held by limited partners	100.00%
CF Real Estate Finance Holdings, L.P.
Related Party Transaction [Line Items]
Equity method investment				$ 100,000