Other Noninterest Income (Loss) and Other Noninterest Expense - Summary of Other Noninterest Income (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Trading Activity, Gains and Losses, Net [Line Items]
Fund management fees	$ 19,195	$ 15,941	$ 13,498
Service-based fee income	7,962	8,767	8,650
Net losses on the sale of certain assets related to our SVBIF business	0	0	(13,934)
Other	25,365	22,074	16,240
Total other noninterest income	40,061	34,162	(1,260)
Client Instruments [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Foreign Currency Transaction Gain (Loss), before Tax	4,215	115	(4,078)
Internal Instruments [Member]
Trading Activity, Gains and Losses, Net [Line Items]
Foreign Currency Transaction Gain (Loss), before Tax	$ (16,676)	$ (12,735)	$ (21,636)