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- Definition

Limited partnership units exchange ratio.

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- Definition

Share-based compensation arrangement by share-based payment award, number of shares registered.

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- Definition

Share-Based Compensation Arrangement By Share-Based Payment Award, Shares Granted

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Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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Amount of cost to be recognized for nonvested award under share-based payment arrangement. Excludes share and unit options.

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- Definition

Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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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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- Definition

Number of equity instruments other than options outstanding, including both vested and non-vested instruments.

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- Definition

Number of shares authorized for issuance under share-based payment arrangement.

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The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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- Definition

Number of shares issued under share-based payment arrangement.

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- Definition

Number of options vested.

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No definition available.

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Compensation - Narrative (Details)	12 Months Ended
Compensation - Narrative (Details)	Dec. 31, 2023 USD ($) shares	Dec. 31, 2022 USD ($) shares	Dec. 31, 2021 USD ($) shares	Dec. 13, 2017 shares
Share-based Compensation Arrangement by Share-based Payment Award
Limited partnership units exchange ratio	0.4545
Compensation expense (benefit) \| $	$ 124,805,000	$ 122,437,000	$ 301,162,000
Unrecognized compensation expense related to unvested RSUs \| $	67,900,000
Limited Partnership Units
Share-based Compensation Arrangement by Share-based Payment Award
Compensation expense (benefit) \| $	$ 0	$ (4,700,000)	$ (4,600,000)
Non Distribution Earning Units
Share-based Compensation Arrangement by Share-based Payment Award
Award vesting period	4 years
Unit granted during period (in shares)	4,500,000	4,400,000	3,700,000
Number of shares vested and converted (in shares)	11,600,000	11,800,000
Newmark Holdings, L.P.
Share-based Compensation Arrangement by Share-based Payment Award
Limited partnership units exchange ratio	0.4545
NEWMARK Group Inc Parent
Share-based Compensation Arrangement by Share-based Payment Award
Limited partnership units outstanding (in shares)	42,376,966	30,687,954	18,419,613
NEWMARK Group Inc Parent \| Limited Partnership Units
Share-based Compensation Arrangement by Share-based Payment Award
Limited partnership units outstanding (in shares)	3,100,000	3,900,000
Exchangeable partnership units (in shares)	1,500,000	1,500,000
BGC Holdings, L.P.
Share-based Compensation Arrangement by Share-based Payment Award
Limited partnership units outstanding (in shares)	0	5,459,388	8,663,930
BGC Holdings, L.P. \| Limited Partnership Units
Share-based Compensation Arrangement by Share-based Payment Award
Limited partnership units outstanding (in shares)		4,800,000
Exchangeable partnership units (in shares)		2,500,000
Maximum \| NEWMARK Group Inc Parent \| Limited Partnership Units
Share-based Compensation Arrangement by Share-based Payment Award
Award vesting period	7 years
Class A Common Stock
Share-based Compensation Arrangement by Share-based Payment Award
Limited partnership units exchange ratio				1
Class A Common Stock \| NEWMARK Group Inc Parent
Share-based Compensation Arrangement by Share-based Payment Award
Limited partnership units exchange ratio	0.9231
Newmark Equity Plan \| Class A Common Stock
Share-based Compensation Arrangement by Share-based Payment Award
Shares authorized to be delivered pursuant to awards granted (in shares)				400,000,000
Shares registered to be delivered pursuant to awards granted (in shares)	400,000,000
Shares purchased for award (in shares)	95,800,000
Shares available for future awards (in shares)	304,200,000