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Limited partnership units exchange ratio.

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Amount for accounts payable to related parties.

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Area of a real estate property.

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Percentage points added to the reference rate to compute the variable rate on the debt instrument.

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Balance held at close of period in number of shares.

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Term of lessee's operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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Amount of cash outflow from operating lease, excluding payments to bring another asset to condition and location necessary for its intended use.

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The cash inflow from the capital received in cash from a partner in a partnership during the period.

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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.

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Number of new stock issued during the period.

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Related Party Transactions - Other Related Party Transactions and Cantor Rights to Purchase Cantor Units from Newmark Holdings (Details)							1 Months Ended		3 Months Ended		9 Months Ended
	Oct. 25, 2022 USD ($) shares	May 17, 2022 USD ($) shares	Oct. 28, 2021 USD ($) shares	Jun. 28, 2021 USD ($)	Mar. 31, 2021 USD ($) shares	Nov. 30, 2018 USD ($)	Jan. 31, 2022 USD ($) ft²	May 31, 2021 USD ($)	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)	Oct. 31, 2022 shares	Dec. 31, 2021 USD ($)	Jul. 02, 2021 shares	Nov. 30, 2020 shares	May 15, 2020 ft²	Dec. 02, 2019 shares	Nov. 06, 2018	Dec. 13, 2017
Related Party Transaction
Accounts receivable, related parties									$ 0		$ 0			$ 8,262,000
Payables to related parties									$ 11,973,000		11,973,000			$ 10,762,000
Operating lease payments											$ 81,400,000	$ 58,700,000
Limited partnership units exchange ratio									0.4545		0.4545
Proceeds from sales of partnership interest											$ 0	4,025,000
Shares owned (in shares) \| shares															5,278,011	250,742		93,562
Maximum
Related Party Transaction
Remaining lease terms									16 years		16 years
Knotel, Inc.
Related Party Transaction
Due from related party, percentage from sale											10.00%
Common Stock
Related Party Transaction
Limited partnership units exchange ratio																			1
Class A Common Stock
Related Party Transaction
Limited partnership units exchange ratio																				1
Class A Common Stock \| NEWMARK Group Inc Parent
Related Party Transaction
Limited partnership units exchange ratio									0.9365		0.9365
Cantor \| Founding partner interest
Related Party Transaction
Stock issued (in shares) \| shares		184,714	299,910		273,088
Proceeds from sales of partnership interest		$ 763,064	$ 975,064		$ 1,105,598
Cantor \| Founding partner interest \| Subsequent Event
Related Party Transaction
Stock issued (in shares) \| shares	104,701
Proceeds from sales of partnership interest	$ 446,647
Cantor \| Founding partner interest \| Newmark Holdings \| Subsequent Event
Related Party Transaction
Shares owned (in shares) \| shares													0
Cantor \| Limited partner interest
Related Party Transaction
Stock issued (in shares) \| shares		23,562	523,284		735,625
Proceeds from sales of partnership interest		$ 100,079	$ 1,898,363		$ 2,918,919
Cantor \| Limited partner interest \| Subsequent Event
Related Party Transaction
Stock issued (in shares) \| shares	102,454
Proceeds from sales of partnership interest	$ 272,100
Affiliated Persons or Entities \| RKF Retail Holdings LLC \| Sublease Agreeement
Related Party Transaction
Remaining lease terms							6 months										1 year
Area of real estate property \| ft²							21,000										21,000
Affiliated Persons or Entities \| Cantor
Related Party Transaction
Monthly payment on sublease							$ 81,600
Operating lease payments									$ 200,000		$ 700,000
Affiliated Persons or Entities \| BGC Holdings, L.P.
Related Party Transaction
Accounts receivable, related parties								$ 1,100,000
Monthly payment on sublease								$ 15,000
Operating lease payments										$ 100,000		$ 500,000
Employee of chairman
Related Party Transaction
Annual base salary				$ 125,000
Employee of chairman \| Maximum
Related Party Transaction
Annual discretionary bonus rate				30.00%
Employee
Related Party Transaction
Travel and housing reimbursement				$ 250,000
Cantor Credit Agreement \| Cantor
Related Party Transaction
Maximum revolving credit						$ 250,000,000
Basis spread on variable rate						1.00%