Loans (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011
Summary of Loans
Commercial, Total	$ 502,230		$ 460,471
Real Estate, Total	182,610		189,714
Consumer, Total	277,864		289,084
Mortgage warehouse	154,962		251,448
Total loans	1,117,666		1,190,717
Allowance for loan losses	(18,880)	(19,565)	(18,270)	(18,374)	(19,412)	(18,882)
Loans, net	1,098,786		1,172,447
Consumer Loans Auto Financing Receivable [Member]
Summary of Loans
Consumer, Total	137,161		142,149
Home equity line of credit [Member]
Summary of Loans
Consumer, Total	99,839		104,974
Working capital and equipment [Member]
Summary of Loans
Commercial, Total	235,315		198,805
Real estate including agriculture [Member]
Summary of Loans
Commercial, Total	249,220		247,108
Tax exempt loans receivable [Member]
Summary of Loans
Commercial, Total	4,275		4,579
Other commercial loans [Member]
Summary of Loans
Commercial, Total	13,420		9,979
1-4 family [Member]
Summary of Loans
Real Estate, Total	179,007		185,940
Other [Member]
Summary of Loans
Real Estate, Total	3,603		3,774
Recreation consumer loans receivable [Member]
Summary of Loans
Consumer, Total	5,185		5,163
Real estate home improvement loans receivable [Member]
Summary of Loans
Consumer, Total	29,415		29,989
Unsecured Debt [Member]
Summary of Loans
Consumer, Total	3,793		4,194
Other consumer loans [Member]
Summary of Loans
Consumer, Total	$ 2,471		$ 2,615