Accounting for Certain Loans Acquired in a Transfer - Summary of contractually required payments receivable at acquisition (Details 2) (Dupont State Bank, Loans Receivable, USD $) In Thousands, unless otherwise specified	Dec. 31, 2012
Contractually required payments receivable at acquisition:
Total required payments receivable	$ 5,285
Cash flows expected to be collected at acquisition	3,838
Basis in acquired loans at acquisition	3,088
Residential Real Estate - Construction
Contractually required payments receivable at acquisition:
Total required payments receivable
Residential Real Estate - One-to-four family residential
Contractually required payments receivable at acquisition:
Total required payments receivable	2,193
Residential Real Estate - Multi-family residential
Contractually required payments receivable at acquisition:
Total required payments receivable	687
Nonresidential real estate and agricultural land
Contractually required payments receivable at acquisition:
Total required payments receivable	1,530
Land and land development
Contractually required payments receivable at acquisition:
Total required payments receivable	750
Commercial
Contractually required payments receivable at acquisition:
Total required payments receivable	73
Consumer and other
Contractually required payments receivable at acquisition:
Total required payments receivable	$ 52