Securities (Details 3) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013 item	Dec. 31, 2012 item
Fair value
Less than 12 months	$ 166,410	$ 48,897
Total	166,410	48,897
Unrealized losses
Less than 12 months	5,090	188
Total	5,090	188
Number of securities	142	14
Government sponsored enterprise obligations
Fair value
Less than 12 months	59,040	29,996
Total	59,040	29,996
Unrealized losses
Less than 12 months	1,484	56
Total	1,484	56
Mortgage-backed securities
Fair value
Less than 12 months	83,927	16,609
Total	83,927	16,609
Unrealized losses
Less than 12 months	3,151	120
Total	3,151	120
Obligations of states and political subdivisions
Fair value
Less than 12 months	23,443	2,292
Total	23,443	2,292
Unrealized losses
Less than 12 months	455	12
Total	$ 455	$ 12