Bank subsidiary (Details 10) (USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended	12 Months Ended
	Jun. 30, 2012	Jun. 30, 2012	Dec. 31, 2011
Carrying amount and the total unpaid principal balance of impaired loans
Recorded investment	$ 113,461	$ 113,461	$ 123,689
Unpaid principal balance	130,278	130,278	142,238
Related Allowance	3,088	3,088	3,704
Average recorded investment	114,025	116,250	129,925
Interest income recognized	1,129	2,535	7,267
With no related allowance recorded
Carrying amount and the total unpaid principal balance of impaired loans
Recorded investment	95,470	95,470	105,811
Unpaid principal balance	111,975	111,975	124,300
Average recorded investment	99,556	101,076	110,109
Interest income recognized	940	2,076	5,726
With an allowance recorded
Carrying amount and the total unpaid principal balance of impaired loans
Recorded investment	17,991	17,991	17,878
Unpaid principal balance	18,303	18,303	17,938
Related Allowance	3,088	3,088	3,704
Average recorded investment	14,469	15,174	19,816
Interest income recognized	189	459	1,541
Residential 1-4 family
Carrying amount and the total unpaid principal balance of impaired loans
Recorded investment	20,925	20,925	22,742
Unpaid principal balance	27,029	27,029	30,139
Related Allowance	324	324	203
Average recorded investment	20,972	21,551	24,912
Interest income recognized	138	302	483
Residential 1-4 family | With no related allowance recorded
Carrying amount and the total unpaid principal balance of impaired loans
Recorded investment	16,405	16,405	19,217
Unpaid principal balance	22,509	22,509	26,614
Average recorded investment	16,897	17,697	21,385
Interest income recognized	79	168	282
Residential 1-4 family | With an allowance recorded
Carrying amount and the total unpaid principal balance of impaired loans
Recorded investment	4,520	4,520	3,525
Unpaid principal balance	4,520	4,520	3,525
Related Allowance	324	324	203
Average recorded investment	4,075	3,854	3,527
Interest income recognized	59	134	201
Commercial real estate
Carrying amount and the total unpaid principal balance of impaired loans
Recorded investment	12,938	12,938	13,397
Unpaid principal balance	12,938	12,938	13,397
Average recorded investment	13,152	13,254	13,404
Interest income recognized	92	237	747
Commercial real estate | With no related allowance recorded
Carrying amount and the total unpaid principal balance of impaired loans
Recorded investment	12,938	12,938	13,397
Unpaid principal balance	12,938	12,938	13,397
Average recorded investment	13,152	13,254	13,404
Interest income recognized	92	237	747
Home equity line of credit
Carrying amount and the total unpaid principal balance of impaired loans
Recorded investment	654	654	711
Unpaid principal balance	1,552	1,552	1,612
Average recorded investment	655	657	954
Interest income recognized		1	6
Home equity line of credit | With no related allowance recorded
Carrying amount and the total unpaid principal balance of impaired loans
Recorded investment	654	654	711
Unpaid principal balance	1,552	1,552	1,612
Average recorded investment	655	657	954
Interest income recognized		1	6
Residential land
Carrying amount and the total unpaid principal balance of impaired loans
Recorded investment	29,836	29,836	38,573
Unpaid principal balance	36,426	36,426	46,988
Related Allowance	2,321	2,321	2,525
Average recorded investment	31,975	33,729	41,556
Interest income recognized	441	1,031	2,382
Residential land | With no related allowance recorded
Carrying amount and the total unpaid principal balance of impaired loans
Recorded investment	22,639	22,639	30,781
Unpaid principal balance	29,170	29,170	39,136
Average recorded investment	24,774	26,337	33,398
Interest income recognized	319	724	1,779
Residential land | With an allowance recorded
Carrying amount and the total unpaid principal balance of impaired loans
Recorded investment	7,197	7,197	7,792
Unpaid principal balance	7,256	7,256	7,852
Related Allowance	2,321	2,321	2,525
Average recorded investment	7,201	7,392	8,158
Interest income recognized	122	307	603
Commercial loans
Carrying amount and the total unpaid principal balance of impaired loans
Recorded investment	49,085	49,085	48,241
Unpaid principal balance	52,310	52,310	50,077
Related Allowance	443	443	976
Average recorded investment	47,248	47,035	49,083
Interest income recognized	458	964	3,649
Commercial loans | With no related allowance recorded
Carrying amount and the total unpaid principal balance of impaired loans
Recorded investment	42,811	42,811	41,680
Unpaid principal balance	45,783	45,783	43,516
Average recorded investment	44,055	43,107	40,952
Interest income recognized	450	946	2,912
Commercial loans | With an allowance recorded
Carrying amount and the total unpaid principal balance of impaired loans
Recorded investment	6,274	6,274	6,561
Unpaid principal balance	6,527	6,527	6,561
Related Allowance	443	443	976
Average recorded investment	3,193	3,928	8,131
Interest income recognized	8	18	737
Consumer loans
Carrying amount and the total unpaid principal balance of impaired loans
Recorded investment	23	23	25
Unpaid principal balance	23	23	25
Average recorded investment	23	24	16
Consumer loans | With no related allowance recorded
Carrying amount and the total unpaid principal balance of impaired loans
Recorded investment	23	23	25
Unpaid principal balance	23	23	25
Average recorded investment	$ 23	$ 24	$ 16