Loans (Details 6) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011	Jun. 30, 2011
Originated Portfolio [Member]
Schedule representing the aging status of the recorded investment in loans by classes
Financing receivable, recorded investment 31 to 60 days past due	$ 20,736	$ 26,252	$ 32,166
Financing receivable, recorded investment 61 to 89 days past due	3,536	11,167	8,641
Financing receivable, recorded investment accruing loans past due 90 days or more	2,566	3,817	3,744
Financing receivable, recorded investment, Nonaccrual loans	74,456	78,394	105,350
Financing receivable recorded investment, Total past due	101,294	119,630	149,901
Financing receivable, recorded investment, current	3,417,253	3,218,872	3,075,278
Financing receivable, recorded investment, Total loans	3,515,110	3,338,502	3,225,179
Originated Portfolio [Member] | Commercial [Member]
Schedule representing the aging status of the recorded investment in loans by classes
Financing receivable, recorded investment 31 to 60 days past due	5,089	5,207	6,480
Financing receivable, recorded investment 61 to 89 days past due	1,838	6,268	2,888
Financing receivable, recorded investment accruing loans past due 90 days or more	300	1,381	629
Financing receivable, recorded investment, Nonaccrual loans	12,673	10,726	14,386
Financing receivable recorded investment, Total past due	19,900	23,582	24,383
Financing receivable, recorded investment, current	767,350	739,953	674,718
Financing receivable, recorded investment, Total loans	787,250	763,535	699,101
Originated Portfolio [Member] | Real estate commercial [Member]
Schedule representing the aging status of the recorded investment in loans by classes
Financing receivable, recorded investment 31 to 60 days past due	8,595	9,967	11,256
Financing receivable, recorded investment 61 to 89 days past due	556	3,241	3,479
Financing receivable, recorded investment accruing loans past due 90 days or more	269	374	143
Financing receivable, recorded investment, Nonaccrual loans	41,691	44,438	57,324
Financing receivable recorded investment, Total past due	51,111	58,020	72,202
Financing receivable, recorded investment, current	839,613	757,047	730,586
Financing receivable, recorded investment, Total loans	890,724	815,067	802,788
Originated Portfolio [Member] | Real estate construction [Member]
Schedule representing the aging status of the recorded investment in loans by classes
Financing receivable, recorded investment 61 to 89 days past due			290
Financing receivable, recorded investment accruing loans past due 90 days or more		287
Financing receivable, recorded investment, Nonaccrual loans	408
Financing receivable recorded investment, Total past due	408	287	290
Financing receivable, recorded investment, current	36,197	54,029	69,791
Financing receivable, recorded investment, Total loans	36,605	54,316	70,081
Originated Portfolio [Member] | Land development [Member]
Schedule representing the aging status of the recorded investment in loans by classes
Financing receivable, recorded investment 31 to 60 days past due	728		209
Financing receivable, recorded investment 61 to 89 days past due	187
Financing receivable, recorded investment, Nonaccrual loans	3,077	6,190	8,933
Financing receivable recorded investment, Total past due	3,992	6,190	9,142
Financing receivable, recorded investment, current	24,476	24,065	23,968
Financing receivable, recorded investment, Total loans	28,468	30,255	33,110
Originated Portfolio [Member] | Real estate residential [Member]
Schedule representing the aging status of the recorded investment in loans by classes
Financing receivable, recorded investment 31 to 60 days past due	2,568	5,591	7,284
Financing receivable, recorded investment 61 to 89 days past due	94	76	226
Financing receivable, recorded investment accruing loans past due 90 days or more	840	752	1,729
Financing receivable, recorded investment, Nonaccrual loans	12,613	12,573	17,809
Financing receivable recorded investment, Total past due	16,115	18,992	27,048
Financing receivable, recorded investment, current	840,900	821,760	774,968
Financing receivable, recorded investment, Total loans	857,015	840,752	802,016
Originated Portfolio [Member] | Consumer installment [Member]
Schedule representing the aging status of the recorded investment in loans by classes
Financing receivable, recorded investment 31 to 60 days past due	2,743	3,449	4,302
Financing receivable, recorded investment 61 to 89 days past due	201	1,174	1,056
Financing receivable, recorded investment, Nonaccrual loans	1,182	1,707	3,205
Financing receivable recorded investment, Total past due	4,126	6,330	8,563
Financing receivable, recorded investment, current	528,757	474,614	503,766
Financing receivable, recorded investment, Total loans	532,883	480,944	512,329
Originated Portfolio [Member] | Home equity [Member]
Schedule representing the aging status of the recorded investment in loans by classes
Financing receivable, recorded investment 31 to 60 days past due	1,013	2,038	2,635
Financing receivable, recorded investment 61 to 89 days past due	660	408	702
Financing receivable, recorded investment accruing loans past due 90 days or more	1,157	1,023	1,243
Financing receivable, recorded investment, Nonaccrual loans	2,812	2,760	3,693
Financing receivable recorded investment, Total past due	5,642	6,229	8,273
Financing receivable, recorded investment, current	376,523	347,404	297,481
Financing receivable, recorded investment, Total loans	382,165	353,633	305,754
Acquired Portfolio [Member]
Schedule representing the aging status of the recorded investment in loans by classes
Financing receivable, recorded investment 31 to 60 days past due	1,418	3,192	1,052
Financing receivable, recorded investment 61 to 89 days past due		273	169
Financing receivable, recorded investment accruing loans past due 90 days or more	13,555	17,375	18,570
Financing receivable, recorded investment, Nonaccrual loans
Financing receivable recorded investment, Total past due	14,973	20,840	19,791
Financing receivable, recorded investment, current	432,259	471,943	503,040
Financing receivable, recorded investment, Total loans	447,232	492,783	522,831
Acquired Portfolio [Member] | Commercial [Member]
Schedule representing the aging status of the recorded investment in loans by classes
Financing receivable, recorded investment 31 to 60 days past due	57	394	18
Financing receivable, recorded investment 61 to 89 days past due
Financing receivable, recorded investment accruing loans past due 90 days or more	5,919	7,808	7,659
Financing receivable, recorded investment, Nonaccrual loans
Financing receivable recorded investment, Total past due	5,976	8,202	7,677
Financing receivable, recorded investment, current	122,126	123,413	135,626
Financing receivable, recorded investment, Total loans	128,102	131,615	143,303
Acquired Portfolio [Member] | Real estate commercial [Member]
Schedule representing the aging status of the recorded investment in loans by classes
Financing receivable, recorded investment 31 to 60 days past due	1,016	1,820	368
Financing receivable, recorded investment 61 to 89 days past due
Financing receivable, recorded investment accruing loans past due 90 days or more	3,291	2,592	4,235
Financing receivable, recorded investment, Nonaccrual loans
Financing receivable recorded investment, Total past due	4,307	4,412	4,603
Financing receivable, recorded investment, current	224,624	252,520	258,215
Financing receivable, recorded investment, Total loans	228,931	256,932	262,818
Acquired Portfolio [Member] | Real estate construction [Member]
Schedule representing the aging status of the recorded investment in loans by classes
Financing receivable, recorded investment 61 to 89 days past due
Financing receivable, recorded investment accruing loans past due 90 days or more		156	152
Financing receivable, recorded investment, Nonaccrual loans
Financing receivable recorded investment, Total past due		156	152
Financing receivable, recorded investment, current	17,933	18,883	20,919
Financing receivable, recorded investment, Total loans	17,933	19,039	21,071
Acquired Portfolio [Member] | Land development [Member]
Schedule representing the aging status of the recorded investment in loans by classes
Financing receivable, recorded investment 31 to 60 days past due
Financing receivable, recorded investment 61 to 89 days past due
Financing receivable, recorded investment accruing loans past due 90 days or more	3,607	4,780	5,045
Financing receivable, recorded investment, Nonaccrual loans
Financing receivable recorded investment, Total past due	3,607	4,780	5,045
Financing receivable, recorded investment, current	7,614	9,786	13,044
Financing receivable, recorded investment, Total loans	11,221	14,566	18,089
Acquired Portfolio [Member] | Real estate residential [Member]
Schedule representing the aging status of the recorded investment in loans by classes
Financing receivable, recorded investment 31 to 60 days past due	75	288	128
Financing receivable, recorded investment 61 to 89 days past due
Financing receivable, recorded investment accruing loans past due 90 days or more	426	1,577	1,094
Financing receivable, recorded investment, Nonaccrual loans
Financing receivable recorded investment, Total past due	501	1,865	1,222
Financing receivable, recorded investment, current	15,698	19,099	22,622
Financing receivable, recorded investment, Total loans	16,199	20,964	23,844
Acquired Portfolio [Member] | Consumer installment [Member]
Schedule representing the aging status of the recorded investment in loans by classes
Financing receivable, recorded investment 31 to 60 days past due	12	49	168
Financing receivable, recorded investment 61 to 89 days past due		11	62
Financing receivable, recorded investment accruing loans past due 90 days or more
Financing receivable, recorded investment, Nonaccrual loans
Financing receivable recorded investment, Total past due	12	60	230
Financing receivable, recorded investment, current	2,388	3,054	4,846
Financing receivable, recorded investment, Total loans	2,400	3,114	5,076
Acquired Portfolio [Member] | Home equity [Member]
Schedule representing the aging status of the recorded investment in loans by classes
Financing receivable, recorded investment 31 to 60 days past due	258	641	370
Financing receivable, recorded investment 61 to 89 days past due		262	107
Financing receivable, recorded investment accruing loans past due 90 days or more	312	462	385
Financing receivable, recorded investment, Nonaccrual loans
Financing receivable recorded investment, Total past due	570	1,365	862
Financing receivable, recorded investment, current	41,826	45,188	47,768
Financing receivable, recorded investment, Total loans	$ 42,446	$ 46,553	$ 48,630