Fair Value Measurements - Summary of Categorization of Assets and Liabilities Measured at Fair Value (Detail) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Liabilities:
Deferred consideration (Note 10)	$ 200,290	$ 228,062
Fair Value, Measurements, Recurring [Member]
Assets:
Cash equivalents	930	11,488
Total	148,590	138,654
Liabilities:
Deferred consideration (Note 10)	200,290	228,062
Fair Value, Measurements, Recurring [Member] \| Securrency Convertible Note [Member]
Investments in Convertible Notes
Investments, Fair value disclosure	14,500
Fair Value, Measurements, Recurring [Member] \| ETFs [Member]
Assets:
Financial instruments owned, at fair value	23,772	18,812
Fair Value, Measurements, Recurring [Member] \| Pass-through GSEs [Member]
Assets:
Financial instruments owned, at fair value	96,837	106,245
Fair Value, Measurements, Recurring [Member] \| Corporate Bonds [Member]
Assets:
Financial instruments owned, at fair value	885	2,109
Fair Value, Measurements, Recurring [Member] \| U.S. treasuries
Assets:
Financial instruments owned, at fair value	2,980
Fair Value, Measurements, Recurring [Member] \| Other Assets Seed Capital [Member]
Assets:
Financial instruments owned, at fair value	1,765
Fair Value, Measurements, Nonrecurring [Member] \| Other Investments [Member]
Assets:
Investment owned, at fair value	312
Securrency - Series A convertible preferred stock \| Fair Value, Measurements, Nonrecurring [Member]
Assets:
Investment owned, at fair value		8,488
Fnality Convertible Note [Member] \| Fair Value, Measurements, Recurring [Member]
Investments in Convertible Notes
Investments, Fair value disclosure	6,921
Level 1 [Member] \| Fair Value, Measurements, Recurring [Member]
Assets:
Cash equivalents	930	11,488
Total	50,972	55,020
Liabilities:
Deferred consideration (Note 10)	0	0
Level 1 [Member] \| Fair Value, Measurements, Recurring [Member] \| Securrency Convertible Note [Member]
Investments in Convertible Notes
Investments, Fair value disclosure	0
Level 1 [Member] \| Fair Value, Measurements, Recurring [Member] \| ETFs [Member]
Assets:
Financial instruments owned, at fair value	23,772	18,812
Level 1 [Member] \| Fair Value, Measurements, Recurring [Member] \| Pass-through GSEs [Member]
Assets:
Financial instruments owned, at fair value	23,290	24,720
Level 1 [Member] \| Fair Value, Measurements, Recurring [Member] \| Corporate Bonds [Member]
Assets:
Financial instruments owned, at fair value	0	0
Level 1 [Member] \| Fair Value, Measurements, Recurring [Member] \| U.S. treasuries
Assets:
Financial instruments owned, at fair value	2,980
Level 1 [Member] \| Fair Value, Measurements, Recurring [Member] \| Other Assets Seed Capital [Member]
Assets:
Financial instruments owned, at fair value	0
Level 1 [Member] \| Fair Value, Measurements, Nonrecurring [Member] \| Other Investments [Member]
Assets:
Investment owned, at fair value	0
Level 1 [Member] \| Securrency - Series A convertible preferred stock \| Fair Value, Measurements, Nonrecurring [Member]
Assets:
Investment owned, at fair value		0
Level 1 [Member] \| Fnality Convertible Note [Member] \| Fair Value, Measurements, Recurring [Member]
Investments in Convertible Notes
Investments, Fair value disclosure	0
Level 2 [Member] \| Fair Value, Measurements, Recurring [Member]
Assets:
Cash equivalents	0	0
Total	76,197	83,634
Liabilities:
Deferred consideration (Note 10)	0	0
Level 2 [Member] \| Fair Value, Measurements, Recurring [Member] \| Securrency Convertible Note [Member]
Investments in Convertible Notes
Investments, Fair value disclosure	0
Level 2 [Member] \| Fair Value, Measurements, Recurring [Member] \| ETFs [Member]
Assets:
Financial instruments owned, at fair value	0	0
Level 2 [Member] \| Fair Value, Measurements, Recurring [Member] \| Pass-through GSEs [Member]
Assets:
Financial instruments owned, at fair value	73,547	81,525
Level 2 [Member] \| Fair Value, Measurements, Recurring [Member] \| Corporate Bonds [Member]
Assets:
Financial instruments owned, at fair value	885	2,109
Level 2 [Member] \| Fair Value, Measurements, Recurring [Member] \| U.S. treasuries
Assets:
Financial instruments owned, at fair value	0
Level 2 [Member] \| Fair Value, Measurements, Recurring [Member] \| Other Assets Seed Capital [Member]
Assets:
Financial instruments owned, at fair value	1,765
Level 2 [Member] \| Fair Value, Measurements, Nonrecurring [Member] \| Other Investments [Member]
Assets:
Investment owned, at fair value	0
Level 2 [Member] \| Securrency - Series A convertible preferred stock \| Fair Value, Measurements, Nonrecurring [Member]
Assets:
Investment owned, at fair value		0
Level 2 [Member] \| Fnality Convertible Note [Member] \| Fair Value, Measurements, Recurring [Member]
Investments in Convertible Notes
Investments, Fair value disclosure	0
Level 3 [Member] \| Fair Value, Measurements, Recurring [Member]
Assets:
Cash equivalents	0	0
Total	21,421	0
Liabilities:
Deferred consideration (Note 10)	200,290	228,062
Level 3 [Member] \| Fair Value, Measurements, Recurring [Member] \| Securrency Convertible Note [Member]
Investments in Convertible Notes
Investments, Fair value disclosure	14,500
Level 3 [Member] \| Fair Value, Measurements, Recurring [Member] \| ETFs [Member]
Assets:
Financial instruments owned, at fair value	0	0
Level 3 [Member] \| Fair Value, Measurements, Recurring [Member] \| Pass-through GSEs [Member]
Assets:
Financial instruments owned, at fair value	0	0
Level 3 [Member] \| Fair Value, Measurements, Recurring [Member] \| Corporate Bonds [Member]
Assets:
Financial instruments owned, at fair value	0	0
Level 3 [Member] \| Fair Value, Measurements, Recurring [Member] \| U.S. treasuries
Assets:
Financial instruments owned, at fair value	0
Level 3 [Member] \| Fair Value, Measurements, Recurring [Member] \| Other Assets Seed Capital [Member]
Assets:
Financial instruments owned, at fair value	0
Level 3 [Member] \| Fair Value, Measurements, Nonrecurring [Member] \| Other Investments [Member]
Assets:
Investment owned, at fair value	312
Level 3 [Member] \| Securrency - Series A convertible preferred stock \| Fair Value, Measurements, Nonrecurring [Member]
Assets:
Investment owned, at fair value		$ 8,488
Level 3 [Member] \| Fnality Convertible Note [Member] \| Fair Value, Measurements, Recurring [Member]
Investments in Convertible Notes
Investments, Fair value disclosure	$ 6,921

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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Value of the investment at close of period. For schedules of investments that are categorized, the value would be aggregated by category. For investment in and advances to affiliates, if operations of any controlled companies are different in character from those of the company, group such affiliates within divisions and by type of activities.

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Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method.

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Fair value of financial instruments held by a broker-dealer for their own account (proprietary securities) for trading or investment purposes determined by management based upon quoted prices of a financial instrument with similar characteristics or on a valuation technique or model.

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