Loans and Allowance for Loan Losses (Details 2) (Acquired loans, USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010
Loans and Allowance for Loan Losses
Total covered loans	$ 332,874		$ 394,495	$ 369,658
Total non-covered loans	227,184		7,706	9,683
Total acquired loans	560,058		402,201	379,341
Less allowance for acquired loan losses	(35,813)	(34,355)	(31,620)	(25,545)	(25,833)
Loans, net	524,245		370,581	353,796		321,038
Loans Impaired at Acquisition
Loans and Allowance for Loan Losses
Total covered loans	133,729		167,334	177,747
Total non-covered loans	30,040		3,496	5,282
Total acquired loans	163,769		170,830	183,029
Less allowance for acquired loan losses	(26,722)		(23,875)	(25,545)
Loans, net	137,047		146,955	157,484		143,059
Loans Not Impaired at Acquisition
Loans and Allowance for Loan Losses
Total covered loans	199,145		227,161	191,911
Total non-covered loans	197,144		4,210	4,401
Total acquired loans	396,289		231,371	196,312
Less allowance for acquired loan losses	(9,091)		(7,745)
Loans, net	387,198		223,626	196,312		177,979
Commercial loans greater than or equal to $1 million-CBT
Loans and Allowance for Loan Losses
Total covered loans	54,826		60,829	72,628
Total acquired loans	54,826			72,628
Less allowance for acquired loan losses	(16,871)	(16,850)	(16,706)	(16,807)	(19,084)
Commercial loans greater than or equal to $1 million-CBT | Loans Impaired at Acquisition
Loans and Allowance for Loan Losses
Total covered loans	20,442		24,073	31,634
Commercial loans greater than or equal to $1 million-CBT | Loans Not Impaired at Acquisition
Loans and Allowance for Loan Losses
Total covered loans	34,384		36,756	40,994
Commercial real estate
Loans and Allowance for Loan Losses
Total covered loans	85,532		107,465	84,449
Total non-covered loans	81,002		862	477
Total acquired loans	166,534			84,926
Less allowance for acquired loan losses	(1,812)	(1,392)	(1,318)	(1,318)
Commercial real estate | Loans Impaired at Acquisition
Loans and Allowance for Loan Losses
Total covered loans	30,776		39,685	36,699
Total non-covered loans	11,937		305	335
Commercial real estate | Loans Not Impaired at Acquisition
Loans and Allowance for Loan Losses
Total covered loans	54,756		67,780	47,750
Total non-covered loans	69,065		557	142
Commercial real estate construction and development
Loans and Allowance for Loan Losses
Total covered loans	40,131		50,953	51,112
Total non-covered loans	25,584		52	38
Total acquired loans	65,715			51,150
Less allowance for acquired loan losses	(3,238)	(2,057)
Commercial real estate construction and development | Loans Impaired at Acquisition
Loans and Allowance for Loan Losses
Total covered loans	21,795		29,528	32,437
Total non-covered loans	9,068		5	28
Commercial real estate construction and development | Loans Not Impaired at Acquisition
Loans and Allowance for Loan Losses
Total covered loans	18,336		21,425	18,675
Total non-covered loans	16,516		47	10
Residential real estate
Loans and Allowance for Loan Losses
Total covered loans	109,849		123,448	114,301
Total non-covered loans	100,649		974	737
Total acquired loans	210,498			115,038
Less allowance for acquired loan losses	(3,911)	(3,868)	(5,026)	(1,464)
Residential real estate | Loans Impaired at Acquisition
Loans and Allowance for Loan Losses
Total covered loans	42,493		50,834	52,877
Total non-covered loans	5,874		224	242
Residential real estate | Loans Not Impaired at Acquisition
Loans and Allowance for Loan Losses
Total covered loans	67,356		72,614	61,424
Total non-covered loans	94,775		750	495
Residential real estate-junior lien
Loans and Allowance for Loan Losses
Total covered loans	2,718		4,778	3,042
Total non-covered loans			186
Total acquired loans	2,718			3,042
Less allowance for acquired loan losses	(462)	(446)	(445)	(462)	(462)
Residential real estate-junior lien | Loans Impaired at Acquisition
Loans and Allowance for Loan Losses
Total covered loans	1,288		1,383	1,728
Residential real estate-junior lien | Loans Not Impaired at Acquisition
Loans and Allowance for Loan Losses
Total covered loans	1,430		3,395	1,314
Total non-covered loans			186
Home equity loans
Loans and Allowance for Loan Losses
Total covered loans	1,367		1,364	1,370
Total non-covered loans	24		23	39
Total acquired loans	1,391			1,409
Less allowance for acquired loan losses	(42)	(21)
Home equity loans | Loans Impaired at Acquisition
Loans and Allowance for Loan Losses
Total covered loans	513		510	442
Total non-covered loans	21		20	37
Home equity loans | Loans Not Impaired at Acquisition
Loans and Allowance for Loan Losses
Total covered loans	854		854	928
Total non-covered loans	3		3	2
Consumer
Loans and Allowance for Loan Losses
Total covered loans	5,731		5,096	7,366
Total non-covered loans	6,436		2,800	4,354
Total acquired loans	12,167			11,720
Less allowance for acquired loan losses	(73)	(10)
Consumer | Loans Impaired at Acquisition
Loans and Allowance for Loan Losses
Total covered loans	1,802		2,669	3,937
Total non-covered loans	1,783		2,723	4,343
Consumer | Loans Not Impaired at Acquisition
Loans and Allowance for Loan Losses
Total covered loans	3,929		2,427	3,429
Total non-covered loans	4,653		77	11
Commercial and industrial
Loans and Allowance for Loan Losses
Total covered loans	27,844		36,502	29,464
Total non-covered loans	13,489		2,809	4,038
Total acquired loans	41,333			33,502
Less allowance for acquired loan losses	(4,749)	(4,583)	(4,564)	(1,929)	(1,234)
Commercial and industrial | Loans Impaired at Acquisition
Loans and Allowance for Loan Losses
Total covered loans	9,916		14,800	12,396
Total non-covered loans	1,357		219	297
Commercial and industrial | Loans Not Impaired at Acquisition
Loans and Allowance for Loan Losses
Total covered loans	17,928		21,702	17,068
Total non-covered loans	12,132		2,590	3,741
Single pay
Loans and Allowance for Loan Losses
Total covered loans	4,876		4,060	5,926
Total acquired loans	4,876			5,926
Less allowance for acquired loan losses	(4,655)	(5,128)	(3,561)	(3,565)	(5,053)
Single pay | Loans Impaired at Acquisition
Loans and Allowance for Loan Losses
Total covered loans	4,704		3,852	5,597
Single pay | Loans Not Impaired at Acquisition
Loans and Allowance for Loan Losses
Total covered loans	$ 172		$ 208	$ 329