Other Noninterest Income (Loss) and Other Noninterest Expense - Summary of Other Noninterest Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Other Income and Expenses [Abstract]
Client services	$ 19,867	$ 15,944	$ 10,692
Data processing services	9,014	7,316	8,079
Telephone	9,793	9,398	7,250
Postage and supplies	2,851	3,154	3,196
Dues and publications	2,828	2,476	2,549
Other	17,890	19,999	12,939
Total other noninterest expense	$ 62,243	$ 58,287	$ 44,705