Bank subsidiary (Details 11) (Class of financing receivables, USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended	12 Months Ended
	Jun. 30, 2013	Jun. 30, 2013	Dec. 31, 2012
Recorded investment:
With no related allowance recorded	$ 24,212	$ 24,212	$ 30,120
With an allowance recorded	34,337	34,337	34,641
Recorded investment	58,549	58,549	64,761
Unpaid principal balance:
With no related allowance recorded	31,841	31,841	42,189
With an allowance recorded	35,810	35,810	35,919
Unpaid principal balance	67,651	67,651	78,108
Related Allowance	6,772	6,772	6,799
Average recorded investment:
With no related allowance recorded	25,932	28,312	71,308
With an allowance recorded	36,862	36,039	21,382
Average recorded investment	62,794	64,351	92,690
Interest income recognized:
With no related allowance recorded	221	452	2,703
With an allowance recorded	315	534	848
Interest income recognized	536	986	3,551
Residential 1-4 family
Recorded investment:
With no related allowance recorded	10,921	10,921	14,633
With an allowance recorded	7,172	7,172	4,803
Recorded investment	18,093	18,093	19,436
Unpaid principal balance:
With no related allowance recorded	14,527	14,527	20,247
With an allowance recorded	7,193	7,193	4,803
Unpaid principal balance	21,720	21,720	25,050
Related Allowance	944	944	384
Average recorded investment:
With no related allowance recorded	12,380	13,568	16,688
With an allowance recorded	7,069	6,039	4,204
Average recorded investment	19,449	19,607	20,892
Interest income recognized:
With no related allowance recorded	98	232	294
With an allowance recorded	75	176	250
Interest income recognized	173	408	544
Commercial real estate
Recorded investment:
With no related allowance recorded			2,929
With an allowance recorded	3,811	3,811	3,821
Recorded investment	3,811	3,811	6,750
Unpaid principal balance:
With no related allowance recorded			2,929
With an allowance recorded	3,834	3,834	3,840
Unpaid principal balance	3,834	3,834	6,769
Related Allowance	820	820	535
Average recorded investment:
With no related allowance recorded		1,604	7,771
With an allowance recorded	8,341	7,221	1,295
Average recorded investment	8,341	8,825	9,066
Interest income recognized:
With no related allowance recorded			237
With an allowance recorded	151	151
Interest income recognized	151	151	237
Home equity line of credit
Recorded investment:
With no related allowance recorded	536	536	581
Recorded investment	536	536	581
Unpaid principal balance:
With no related allowance recorded	1,077	1,077	1,374
Unpaid principal balance	1,077	1,077	1,374
Average recorded investment:
With no related allowance recorded	637	646	632
With an allowance recorded			26
Average recorded investment	637	646	658
Interest income recognized:
With no related allowance recorded			1
Interest income recognized			1
Residential land
Recorded investment:
With no related allowance recorded	8,429	8,429	7,691
With an allowance recorded	6,229	6,229	9,984
Recorded investment	14,658	14,658	17,675
Unpaid principal balance:
With no related allowance recorded	9,809	9,809	10,624
With an allowance recorded	6,356	6,356	10,364
Unpaid principal balance	16,165	16,165	20,988
Related Allowance	1,641	1,641	3,221
Average recorded investment:
With no related allowance recorded	8,502	8,167	21,589
With an allowance recorded	6,379	7,632	7,428
Average recorded investment	14,881	15,799	29,017
Interest income recognized:
With no related allowance recorded	122	219	1,185
With an allowance recorded	89	202	575
Interest income recognized	211	421	1,760
Commercial loans
Recorded investment:
With no related allowance recorded	4,306	4,306	4,265
With an allowance recorded	17,125	17,125	16,033
Recorded investment	21,431	21,431	20,298
Unpaid principal balance:
With no related allowance recorded	6,408	6,408	6,994
With an allowance recorded	18,427	18,427	16,912
Unpaid principal balance	24,835	24,835	23,906
Related Allowance	3,367	3,367	2,659
Average recorded investment:
With no related allowance recorded	4,393	4,306	24,605
With an allowance recorded	15,073	15,147	8,429
Average recorded investment	19,466	19,453	33,034
Interest income recognized:
With no related allowance recorded	1	1	986
With an allowance recorded		5	23
Interest income recognized	1	6	1,009
Consumer loans
Recorded investment:
With no related allowance recorded	20	20	21
Recorded investment	20	20	21
Unpaid principal balance:
With no related allowance recorded	20	20	21
Unpaid principal balance	20	20	21
Average recorded investment:
With no related allowance recorded	20	21	23
Average recorded investment	$ 20	$ 21	$ 23