Noninterest Income and Expenses (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012
Components of other noninterest income
Service charges on deposit accounts	$ 3,140				$ 3,527
ATM and interchange fees	1,875				1,819
Other service fees	559				603
Mortgage banking service fees	416				372
Change in value of mortgage servicing rights	(61)				(369)
Total service charges and fees	5,929				5,952
Gain on sale of loans	2,294				1,650
Commissions on sale of non-deposit investment products	761				819
Increase in cash value of life insurance	426				450
Change in indemnification asset	(101)				(353)
Gain (loss) on sale of foreclosed assets	551				(358)
Sale of customer checks	91				73
Lease brokerage income	117				58
Loss on disposal of fixed assets	(16)				(235)
Commission rebates					(16)
Other	166				225
Total other noninterest income	4,289				2,313
Total noninterest income	$ 10,218	$ 10,011	$ 9,127	$ 10,577	$ 8,265