Loans and Allowance for Loan Losses (Details 6) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Allowance for loan losses:
Charge-offs	$ (21,930,000)	$ (29,209,000)	$ (46,817,000)
Recoveries	3,756,000	2,409,000	2,559,000
Provision	13,619,000	30,236,000
Non-acquired loans
Allowance for loan losses:
Balance at the beginning of the period	49,367,000	47,512,000	37,488,000
Charge-offs	(21,930,000)	(29,209,000)	(46,817,000)
Recoveries	3,756,000	2,409,000	2,559,000
Provision	13,185,000	28,655,000	54,282,000
Balance at the end of the period	44,378,000	49,367,000	47,512,000
Loans individually evaluated for impairment	4,879,000	4,413,000	4,136,000
Loans collectively evaluated for impairment	39,499,000	44,954,000	43,376,000
Loans:
Loans individually evaluated for impairment	47,235,000	62,051,000	50,613,000
Loans collectively evaluated for impairment	2,523,768,000	2,408,514,000	2,245,587,000
Total loans	2,571,003,000	2,470,565,000	2,296,200,000
Non-acquired loans | Construction & Land Development
Allowance for loan losses:
Balance at the beginning of the period	12,373,000	14,242,000	9,169,000
Charge-offs	(8,454,000)	(11,848,000)	(19,150,000)
Recoveries	1,428,000	518,000	785,000
Provision	5,489,000	9,461,000	23,438,000
Balance at the end of the period	10,836,000	12,373,000	14,242,000
Loans individually evaluated for impairment	1,573,000	1,646,000	1,718,000
Loans collectively evaluated for impairment	9,263,000	10,727,000	12,524,000
Loans:
Loans individually evaluated for impairment	13,549,000	24,749,000	23,081,000
Loans collectively evaluated for impairment	259,871,000	286,096,000	368,906,000
Total loans	273,420,000	310,845,000	391,987,000
Non-acquired loans | Commercial Non-owner Occupied
Allowance for loan losses:
Balance at the beginning of the period	6,109,000	6,428,000	5,792,000
Charge-offs	(2,348,000)	(3,805,000)	(3,011,000)
Recoveries	282,000	144,000	29,000
Provision	878,000	3,342,000	3,618,000
Balance at the end of the period	4,921,000	6,109,000	6,428,000
Loans individually evaluated for impairment	411,000	706,000	1,444,000
Loans collectively evaluated for impairment	4,510,000	5,403,000	4,984,000
Loans:
Loans individually evaluated for impairment	5,344,000	12,040,000	10,948,000
Loans collectively evaluated for impairment	284,727,000	287,658,000	309,255,000
Total loans	290,071,000	299,698,000	320,203,000
Non-acquired loans | Commercial Owner Occupied
Allowance for loan losses:
Balance at the beginning of the period	10,356,000	7,814,000	5,978,000
Charge-offs	(2,781,000)	(2,346,000)	(2,625,000)
Recoveries	5,000	158,000	126,000
Provision	1,163,000	4,730,000	4,335,000
Balance at the end of the period	8,743,000	10,356,000	7,814,000
Loans individually evaluated for impairment	648,000	1,510,000	830,000
Loans collectively evaluated for impairment	8,095,000	8,846,000	6,984,000
Loans:
Loans individually evaluated for impairment	20,212,000	17,717,000	10,747,000
Loans collectively evaluated for impairment	763,940,000	725,173,000	567,840,000
Total loans	784,152,000	742,890,000	578,587,000
Non-acquired loans | Consumer Owner Occupied
Allowance for loan losses:
Balance at the beginning of the period	7,453,000	6,060,000	4,635,000
Charge-offs	(1,850,000)	(3,365,000)	(7,285,000)
Recoveries	124,000	224,000	149,000
Provision	8,410,000	4,534,000	8,561,000
Balance at the end of the period	6,568,000	7,453,000	6,060,000
Loans individually evaluated for impairment	213,000	262,000	80,000
Loans collectively evaluated for impairment	6,355,000	7,191,000	5,980,000
Loans:
Loans individually evaluated for impairment	1,954,000	2,594,000	1,540,000
Loans collectively evaluated for impairment	432,549,000	388,935,000	323,930,000
Total loans	434,503,000	391,529,000	325,470,000
Non-acquired loans | Home Equity
Allowance for loan losses:
Balance at the beginning of the period	4,269,000	4,424,000	3,751,000
Charge-offs	(1,394,000)	(2,159,000)	(2,490,000)
Recoveries	600,000	132,000	45,000
Provision	151,000	1,872,000	3,118,000
Balance at the end of the period	3,626,000	4,269,000	4,424,000
Loans collectively evaluated for impairment	3,626,000	4,269,000	4,424,000
Loans:
Loans collectively evaluated for impairment	255,284,000	264,986,000	263,961,000
Total loans	255,284,000	264,986,000	263,961,000
Non-acquired loans | Commercial & Industrial
Allowance for loan losses:
Balance at the beginning of the period	3,901,000	4,313,000	4,330,000
Charge-offs	(2,033,000)	(1,872,000)	(9,138,000)
Recoveries	228,000	295,000	713,000
Provision	2,843,000	1,165,000	8,408,000
Balance at the end of the period	4,939,000	3,901,000	4,313,000
Loans individually evaluated for impairment	1,030,000		36,000
Loans collectively evaluated for impairment	3,909,000	3,901,000	4,277,000
Loans:
Loans individually evaluated for impairment	1,783,000	1,576,000	1,144,000
Loans collectively evaluated for impairment	277,980,000	218,878,000	201,843,000
Total loans	279,763,000	220,454,000	202,987,000
Non-acquired loans | Other Income Producing Property
Allowance for loan losses:
Balance at the beginning of the period	3,636,000	2,834,000	2,375,000
Charge-offs	(924,000)	(2,366,000)	(338,000)
Recoveries	361,000	293,000	6,000
Provision	674,000	2,875,000	791,000
Balance at the end of the period	3,747,000	3,636,000	2,834,000
Loans individually evaluated for impairment	1,004,000	289,000	28,000
Loans collectively evaluated for impairment	2,743,000	3,347,000	2,806,000
Loans:
Loans individually evaluated for impairment	4,393,000	3,375,000	3,153,000
Loans collectively evaluated for impairment	129,320,000	137,318,000	121,278,000
Total loans	133,713,000	140,693,000	124,431,000
Non-acquired loans | Consumer
Allowance for loan losses:
Balance at the beginning of the period	1,145,000	1,191,000	1,258,000
Charge-offs	(2,146,000)	(1,337,000)	(2,780,000)
Recoveries	728,000	645,000	706,000
Provision	1,054,000	646,000	2,007,000
Balance at the end of the period	781,000	1,145,000	1,191,000
Loans collectively evaluated for impairment	781,000	1,145,000	1,191,000
Loans:
Loans collectively evaluated for impairment	86,934,000	85,342,000	67,768,000
Total loans	86,934,000	85,342,000	67,768,000
Non-acquired loans | Other Loans
Allowance for loan losses:
Balance at the beginning of the period	125,000	206,000	200,000
Charge-offs		(111,000)
Provision	92,000	30,000	6,000
Balance at the end of the period	217,000	125,000	206,000
Loans collectively evaluated for impairment	217,000	125,000	206,000
Loans:
Loans collectively evaluated for impairment	33,163,000	14,128,000	20,806,000
Total loans	$ 33,163,000	$ 14,128,000	$ 20,806,000