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No definition available.

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- Definition

Face (par) amount of debt instrument at time of issuance.

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- Definition

Amount of the fee that accompanies borrowing money under the debt instrument.

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- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

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- Definition

The number of limited partner units outstanding.

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- Definition

Total change in each class of partners' capital accounts during the year due to the sale of units. All partners include general, limited and preferred partners.

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- Definition

Total units issued during the year due to the sale of units. All partners include general, limited and preferred partners.

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- 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.

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No definition available.

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Per share amount received by subsidiary or equity investee for each share of common stock issued or sold in the stock transaction.

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No definition available.

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Related Party Transactions - BGC's 2018 Investment in Newmark Holdings (Details) - USD ($)		3 Months Ended
	Mar. 07, 2018	Sep. 26, 2018	Dec. 31, 2020	Dec. 31, 2019	Nov. 06, 2018
BGC Partners LP and its Operating Subsidiaries \| Newmark Units
Related Party Transaction
Purchase of units (units)	16,600,000
Purchase value of units	$ 242,000,000.0
Closing price per share (in dollars per share)	$ 14.57
Limited partners capital account units held by BGC (in shares)	14,800,000
BGC Partners LP and its Operating Subsidiaries \| Newmark Units \| Newmark OpCo
Related Party Transaction
Limited partners capital account units held by BGC (in shares)	7,000,000.0
Cantor
Related Party Transaction
Fees for services		$ 4,000,000.0
Stated interest rate (in percentage)			0.85%	2.45%
Cantor \| 6.125% Senior Notes
Related Party Transaction
Debt instrument face amount					$ 550,000,000.0
Stated interest rate (in percentage)					6.125%
Debt instrument, fee amount					$ 800,000