Condensed Consolidated Statements of Comprehensive Income (unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Statement of Other Comprehensive Income [Abstract]
Net income available to common shareholders	$ 4,502	$ 4,638	$ 11,994	$ 12,258
Investment securities available for sale:
Unrealized gains (losses) arising in period	1,838	2,939	(11,004)	4,489
Reclassification adjustment for net gains realized in earnings (net of tax expense of $121 for the three months ended September 30, 2012, and net of tax expense of $195 and $240 for the nine months ended September 30, 2013 and 2012, respectively.)	0	(224)	(361)	(447)
Income tax provision (benefit) related to unrealized gains (losses)	643	1,029	(3,851)	1,571
Other comprehensive income (loss), net of tax	1,195	1,686	(7,514)	2,471
Total comprehensive income	5,697	6,324	4,480	14,729
Reclassification adjustment for net gains realized in earnings, tax		$ 0	$ 195	$ 240