Other Noninterest Income and Other Noninterest Expense - Summary of Other Noninterest Income (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015		Jun. 30, 2014
Other Income and Expenses [Abstract]
Fund management fees	$ 3,861	$ 3,559	$ 7,583		$ 6,314
Service-based fee income	2,413	2,252	4,519		4,279
Gains (losses) on revaluation of foreign currency instruments	8,306	(685)	(11,853)		293
Other	4,336	3,636	10,989		9,076
Total other noninterest income	$ 18,916	$ 8,762	$ 11,238	[1]	$ 19,962

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