Other Noninterest Income and Other Noninterest Expense - Summary of Other Noninterest Expense (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Other Income and Expenses [Abstract]
Client services	$ 2,586	$ 1,856	$ 4,945	$ 3,791
Data processing services	2,041	1,882	4,268	3,794
Tax credit fund amortization	2,502	1,338	4,530	2,655
Telephone	1,538	1,512	3,286	3,069
Postage and supplies	716	680	1,485	1,218
Dues and publications	636	445	1,133	903
Other	3,108	1,975	4,670	4,193
Total other noninterest expense	$ 13,127	$ 9,688	$ 24,317	$ 19,623