Other Noninterest Income and Other Noninterest Expense - Summary of Other Noninterest Expense (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Other Income and Expenses [Abstract]
Lending and other client related processing costs	$ 3,201	$ 5,539
Telephone	2,377	2,703
Data processing services	2,492	2,582
Dues and publications	850	795
Postage and supplies	667	749
Other	5,107	3,839
Total other noninterest expense	$ 14,694	$ 16,207