Securities (Details 2) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012 security	Dec. 31, 2011 security
Number of Securities
Less than 12 months in an unrealized loss position	37	22
Greater than 12 months in an unrealized loss position	2	2
Total	39	24
Unrealized Losses
Less than 12 months in an unrealized loss position	$ 2,166	$ 2,151
Greater than 12 months in an unrealized loss position	8,747	7,918
Total	10,913	10,069
Fair Value
Less than 12 months in an unrealized loss position	159,695	93,913
Greater than 12 months in an unrealized loss position	9,163	9,974
Total	168,858	103,887
U.S. government agencies
Number of Securities
Less than 12 months in an unrealized loss position	4
Total	4
Unrealized Losses
Less than 12 months in an unrealized loss position	32
Total	32
Fair Value
Less than 12 months in an unrealized loss position	14,156
Total	14,156
U.S. government agency mortgage-backed
Number of Securities
Less than 12 months in an unrealized loss position	2	4
Total	2	4
Unrealized Losses
Less than 12 months in an unrealized loss position	16	19
Total	16	19
Fair Value
Less than 12 months in an unrealized loss position	2,555	27,935
Total	2,555	27,935
States and political subdivisions
Number of Securities
Less than 12 months in an unrealized loss position	1
Total	1
Unrealized Losses
Less than 12 months in an unrealized loss position	5
Total	5
Fair Value
Less than 12 months in an unrealized loss position	1,295
Total	1,295
Corporate bonds
Number of Securities
Less than 12 months in an unrealized loss position	6	11
Total	6	11
Unrealized Losses
Less than 12 months in an unrealized loss position	100	982
Total	100	982
Fair Value
Less than 12 months in an unrealized loss position	12,184	28,605
Total	12,184	28,605
Collateralized mortgage obligations
Number of Securities
Less than 12 months in an unrealized loss position	12	3
Total	12	3
Unrealized Losses
Less than 12 months in an unrealized loss position	870	736
Total	870	736
Fair Value
Less than 12 months in an unrealized loss position	36,439	9,032
Total	36,439	9,032
Asset-backed securities
Number of Securities
Less than 12 months in an unrealized loss position	12	4
Total	12	4
Unrealized Losses
Less than 12 months in an unrealized loss position	1,143	414
Total	1,143	414
Fair Value
Less than 12 months in an unrealized loss position	93,066	28,341
Total	93,066	28,341
Collateralized debt obligations
Number of Securities
Greater than 12 months in an unrealized loss position	2	2
Total	2	2
Unrealized Losses
Greater than 12 months in an unrealized loss position	8,747	7,918
Total	8,747	7,918
Fair Value
Greater than 12 months in an unrealized loss position	9,163	9,974
Total	$ 9,163	$ 9,974