Regulatory Authorities - Additional Information (Detail) - USD ($)	Mar. 31, 2023	Dec. 31, 2022
LFNY [Member]
Regulatory Requirements [Line Items]
Specified fixed percentage, minimum required capital	6.67%
Minimum net capital requirement as defined under exchange act	$ 5,000
Regulatory capital	48,294,000
Regulatory capital in excess of minimum requirement	$ 43,030,000
Aggregate indebtedness to net capital ratio	1.63
LFNY [Member] | Maximum [Member]
Regulatory Requirements [Line Items]
Aggregate indebtedness to net capital ratio	15
U.K. Subsidiaries [Member]
Regulatory Requirements [Line Items]
Regulatory capital	$ 181,434,000
Regulatory capital in excess of minimum requirement	122,490,000
CFLF [Member]
Regulatory Requirements [Line Items]
Regulatory capital		$ 152,442,000
Regulatory capital in excess of minimum requirement		74,403,000
Combined European Regulated Group [Member]
Regulatory Requirements [Line Items]
Regulatory capital		176,343,000
Regulatory capital in excess of minimum requirement		$ 89,905,000
Other U.S. and Non-U.S. Subsidiaries [Member]
Regulatory Requirements [Line Items]
Regulatory capital	150,254,000
Regulatory capital in excess of minimum requirement	$ 123,459,000