Aggregate estimated fair value of deferred compensation awards.

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- Definition

Common stock exchangeable basis.

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- Definition

Estimated fair value of limited partnership units held by executives and non-executive employees, awarded in lieu of cash compensation for salaries, commissions and/or discretionary or guaranteed bonuses.

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- Definition

Estimated fair value of limited partnership units and restricted stock units.

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Limited Partnership Interests Exchange Ratio

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- Definition

Notional value of limited partnership units with post termination pay out amount.

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- Definition

Number Of Common Stock Settled Per Restricted Stock Unit

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- Definition

Number of limited partnership units exchangeable into shares.

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Number of outstanding restricted shares held.

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- Definition

Period over which the sale or transferability of an the equity-based payment award is restricted, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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No definition available.

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- Definition

Restricted shares that were previously issued and then had their restriction released during the period.

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- Definition

Value of shares withheld for tax, related to share-based compensation.

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Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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- Definition

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

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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
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- Definition

The number of limited partner units outstanding.

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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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- Definition

The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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

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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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Number of shares related to Restricted Stock Award forfeited during the period.

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Compensation - Narrative (Detail) $ in Thousands	3 Months Ended		6 Months Ended
Compensation - Narrative (Detail) $ in Thousands	Mar. 31, 2023 USD ($) shares	Mar. 31, 2022 USD ($) shares	Jun. 30, 2022 USD ($)	Dec. 31, 2022 USD ($) shares	Nov. 22, 2021 shares	Nov. 21, 2021 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate number of shares grant of future awards (in shares)	114,100,000
Number of share-equivalent limited partnership units exchangeable into shares (in shares)	1,200,000			1,200,000
Number of common stock settled per restricted stock unit (in shares)	1
Aggregate estimated fair value of limited partnership units and restricted stock units \| $	$ 6,100		$ 5,900
Aggregate estimated fair value of deferred compensation awards \| $	$ 24,500		$ 23,900
Shares, forfeited (in shares)	13,000	0
Number of shares released the restrictions (in shares)	30,000	100,000
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expense related to unvested \| $	$ 36,700
Unrecognized compensation expense related to unvested recognized period	2 years 5 months 12 days
Limited partnership units outstanding (in shares)	9,241,000			12,046,000
Restricted Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Limited partnership units outstanding (in shares)	2,300,000			2,300,000
Minimum \| Restricted Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted shares saleable period	5 years
Maximum \| Restricted Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted shares saleable period	10 years
LPUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock exchangeable basis	1
Limited partnership interests exchange ratio	0.9252
Unrecognized compensation expense related to unvested \| $	$ 83,100
Limited partnership units outstanding (in shares)	103,926,000			110,348,000
LPUs \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted shares, restriction period	2 years
LPUs \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted shares, restriction period	5 years
Newmark
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares released the restrictions (in shares)	16,000	28,000
Number of outstanding restricted shares held (in shares)	1,100,000			1,100,000
Newmark \| LPUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Limited partnership units outstanding (in shares)	9,248,000			9,351,000
Newmark \| LPUs \| REUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Notional value with post-termination pay-out amount \| $	$ 700			$ 700
Aggregate estimated fair value of limited partnership units \| $	$ 300			$ 300
BGC Holdings \| LPUs \| REUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of unvested limited partnership units with post-termination pay-out (in shares)	700,000			800,000
Notional value with post-termination pay-out amount \| $	$ 5,100			$ 8,600
Aggregate estimated fair value of limited partnership units \| $	$ 3,900			$ 3,900
Number of outstanding limited partnership units, unvested (in shares)	100,000			100,000
Class A Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of share-equivalent limited partnership units exchangeable into shares (in shares)	200,000			200,000
Shares, forfeited (in shares)	49,201	0
Class A Common Stock \| Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Value of shares withheld \| $	$ 6,200	$ 5,500
Equity plan \| Class A Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized to be delivered pursuant to awards granted (in shares)					500,000,000	400,000,000