Bank subsidiary (Details 10) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Credit risk profile based on nonaccrual loans
Nonaccrual loans	$ 67,428	$ 64,887
Accruing loans 90 days or more past due	1,628	373
Residential 1-4 family
Credit risk profile based on nonaccrual loans
Nonaccrual loans	25,578	26,721
Commercial real estate
Credit risk profile based on nonaccrual loans
Nonaccrual loans	10,663	6,750
Home equity line of credit
Credit risk profile based on nonaccrual loans
Nonaccrual loans	2,352	2,349
Residential land
Credit risk profile based on nonaccrual loans
Nonaccrual loans	9,249	8,561
Accruing loans 90 days or more past due	1,268
Commercial loans
Credit risk profile based on nonaccrual loans
Nonaccrual loans	19,305	20,222
Accruing loans 90 days or more past due	88	131
Consumer loans
Credit risk profile based on nonaccrual loans
Nonaccrual loans	281	284
Accruing loans 90 days or more past due	$ 272	$ 242