Summary of Other Noninterest Income (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Other Noninterest Income [Line Items]
Fund management fees	$ 10,730	$ 10,753	$ 10,328
Service-based fee income	9,717	8,840	7,554
Unused commitment fees	7,095	6,833	3,534
Loan syndication fees	1,020	1,775
(Losses) gains on revaluation of foreign currency loans, net	(1,821)	(427)	1,945
Currency revaluation (losses) gains	(4,275)	959	764
Other	7,689	6,909	5,836
Total other noninterest income	$ 30,155	$ 35,642	$ 29,961