Other Noninterest Income and Other Noninterest Expense - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Nonoperating expense [Line Items]
Other miscellaneous expense	$ 21,580	$ 30,585	$ 45,242
Other Miscellaneous Expense [Member]
Nonoperating expense [Line Items]
Other miscellaneous expense	$ 2,700	$ 9,600	$ 19,700