Summary of Other Noninterest Expense (Detail) (USD $) In Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Other Noninterest Expense [Line Items]
Telephone	$ 1,610	$ 1,208	$ 4,376	$ 3,438
Data processing services	1,097	1,008	3,589	2,910
Tax credit fund amortization	1,212	1,050	3,366	3,107
Client services	1,289	651	3,128	2,006
Postage and supplies	641	571	1,725	1,645
Dues and publications	465	444	1,166	1,093
Net gain from note repurchases and termination of corresponding interest rate swaps			(3,123)
Other	3,240	2,062	8,226	5,750
Total other noninterest expense	$ 9,554	$ 6,994	$ 22,453	$ 19,949