Quarterly Financial Information (Unaudited) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Summary of quarterly data
Interest income	$ 17,797	$ 18,191	$ 20,894	$ 21,562	$ 22,471	$ 23,321	$ 24,863	$ 25,732	$ 78,444	$ 96,387	$ 110,748
Interest expense	3,789	4,063	4,474	5,683	7,633	7,696	7,805	8,078	18,006	31,212	39,387
Net interest income	14,011	14,128	16,420	15,879	14,838	15,625	17,058	17,654	60,438	65,175	71,361
Provision for loan losses	2,102	30,279	6,264	680	2,386	11,836	8,244	2,192	39,325	24,658	62,427
Net interest income after provision for loan losses	11,909	(16,151)	10,156	15,199	12,452	3,789	8,814	15,462	21,113	40,517	8,934
Non-interest income	6,939	3,752	6,949	5,091	12,021	1,916	5,300	3,988	22,731	23,225	21,893
Non-interest expenses	14,302	17,330	17,043	16,494	16,545	14,569	15,910	16,488	65,169	63,512	68,331
Income (loss) before taxes	4,546	(29,729)	62	3,796	7,928	(8,864)	(1,796)	2,962	(21,325)	230	(37,504)
Income taxes (benefit)	1,950	(2,838)							(888)		(231)
Net income (loss)	$ 2,596	$ (26,891)	$ 62	$ 3,796	$ 7,928	$ (8,864)	$ (1,796)	$ 2,962	$ (20,437)	$ 230	$ (37,273)
Earnings (loss) per share:
Basic earnings (loss)	$ 0.08	$ (0.82)		$ 0.12	$ 0.25	$ (0.29)	$ (0.06)	$ 0.10	$ (0.62)	$ 0.01	$ (1.22)
Diluted earnings (loss)	$ 0.08	$ (0.82)		$ 0.12	$ 0.25	$ (0.29)	$ (0.06)	$ 0.10	$ (0.62)	$ 0.01	$ (1.22)