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, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Other Income and Expenses [Abstract]
Telephone	$ 1,512	$ 1,547	$ 3,069	$ 3,331
Client services	1,856	1,739	3,791	2,992
Data processing services	1,882	1,310	3,794	2,715
Tax credit fund amortization	1,338	962	2,655	2,020
Postage and supplies	680	628	1,218	1,253
Dues and publications	445	557	903	1,031
Other	1,975	2,675	4,193	3,883
Total other noninterest expense	$ 9,688	$ 9,418	$ 19,623	$ 17,225