Regulatory Authorities - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014
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	100,252
Regulatory capital in excess of minimum requirement	97,110
U.K. Subsidiaries [Member]
Regulatory Requirements [Line Items]
Regulatory net capital	92,574
Regulatory capital in excess of minimum requirement	75,634
CFLF [Member]
Regulatory Requirements [Line Items]
Regulatory net capital	140,872
Regulatory capital in excess of minimum requirement	105,079
Other U.S. and Non-U.S. Subsidiaries [Member]
Regulatory Requirements [Line Items]
Regulatory net capital	105,753
Regulatory capital in excess of minimum requirement	$ 77,600