Regulatory Authorities - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013
LFNY [Member]
Regulatory Requirements [Line Items]
Specified fixed percentage, minimum required capital	6.67%
Minimum net capital requirement as defined under securities exchange act	$ 100
Regulatory net capital	110,317
Regulatory capital in excess of minimum requirement	106,944
U.K. Subsidiaries [Member]
Regulatory Requirements [Line Items]
Regulatory net capital	77,786
Regulatory capital in excess of minimum requirement	63,349
CFLF [Member]
Regulatory Requirements [Line Items]
Regulatory net capital	196,109
Regulatory capital in excess of minimum requirement	162,915
Other U.S. and Non-U.S. Subsidiaries [Member]
Regulatory Requirements [Line Items]
Regulatory net capital	113,118
Regulatory capital in excess of minimum requirement	$ 78,848