Other Noninterest Income and Other Noninterest Expense - Summary of Other Noninterest Income (Detail) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Other Noninterest Income [Line Items]
Fund management fees		$ 5,536	$ 4,298	$ 10,705	$ 8,918
Service-based fee income		1,496	2,148	3,391	4,240
Unrealized Gain (Loss) on Derivatives				(8,505)	1,636
Other (3)		5,552	4,966	9,581	7,641
Total other noninterest income	[1]	12,811	9,963	25,232	17,633
Client Instruments
Other Noninterest Income [Line Items]
Gains (losses) on revaluation of internal foreign currency instruments, net (2)		2,375	(133)	5,129	3,521
Internal Instruments
Other Noninterest Income [Line Items]
Gains (losses) on revaluation of internal foreign currency instruments, net (2)		14,596	(5,307)	18,704	(2,816)
Derivatives not designated as hedging instruments | Foreign Exchange Contract
Other Noninterest Income [Line Items]
Unrealized Gain (Loss) on Derivatives		42	(1,384)	905	(1,101)
Derivatives not designated as hedging instruments | Other derivative instruments
Other Noninterest Income [Line Items]
Unrealized Gain (Loss) on Derivatives		185	(65)	650	(2,065)
Other noninterest income | Derivatives not designated as hedging instruments | Foreign Exchange Contract
Other Noninterest Income [Line Items]
Unrealized Gain (Loss) on Derivatives		(14,554)	3,923	(17,799)	1,715
Other noninterest income | Derivatives not designated as hedging instruments | Other derivative instruments
Other Noninterest Income [Line Items]
Unrealized Gain (Loss) on Derivatives		$ (2,190)	$ 68	$ (4,479)	$ (5,586)

[1] Our consolidated statements of income for the three and six months ended June 30, 2016 were modified from prior period's presentation to conform to the current period's presentation, which reflects a new line item to separately disclose net gains on equity warrant assets. In prior periods, net gains on equity warrant assets were reported as a component of gains on derivative instruments, net. We removed the line item gains on derivative instruments, net and reclassified all other gains on derivative instruments, net to other noninterest income.