Loans and Allowance for Loan Losses (Details 7) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Allowance for loan losses:
Provision for loan losses before benefit attributable to FDIC loss share agreements	$ 13,697	$ 60,275	$ 54,282
Benefit attributable to FDIC loss share agreements	(78)	(30,039)
Total provision for loan losses charged to operations	13,619	30,236
Provision for loan losses recorded through the FDIC loss share receivable	78	30,039
Acquired loans
Allowance for loan losses:
Balance at the beginning of the period	31,620
Provision for loan losses before benefit attributable to FDIC loss share agreements	512	31,620
Benefit attributable to FDIC loss share agreements	(78)	(30,039)
Total provision for loan losses charged to operations	434	1,581
Provision for loan losses recorded through the FDIC loss share receivable	78	30,039
Balance at the end of the period	32,132	31,620
Loans collectively evaluated for impairment	32,132	31,620
Loans:
Loans collectively evaluated for impairment	1,074,742	402,201
Total acquired loans	1,074,742	402,201
Acquired loans | Commercial Loans Greater Than or Equal to $1 Million-CBT
Allowance for loan losses:
Balance at the beginning of the period	16,706
Provision for loan losses before benefit attributable to FDIC loss share agreements	(1,298)	16,706
Benefit attributable to FDIC loss share agreements	1,233	(15,871)
Total provision for loan losses charged to operations	(65)	835
Provision for loan losses recorded through the FDIC loss share receivable	(1,233)	15,871
Balance at the end of the period	15,408	16,706
Loans collectively evaluated for impairment	15,408	16,706
Loans:
Loans collectively evaluated for impairment	49,684	60,829
Total acquired loans	49,684	60,829
Acquired loans | Commercial real estate
Allowance for loan losses:
Balance at the beginning of the period	1,318
Provision for loan losses before benefit attributable to FDIC loss share agreements	199	1,318
Benefit attributable to FDIC loss share agreements	(30)	(1,252)
Total provision for loan losses charged to operations	169	66
Provision for loan losses recorded through the FDIC loss share receivable	30	1,252
Balance at the end of the period	1,517	1,318
Loans collectively evaluated for impairment	1,517	1,318
Loans:
Loans collectively evaluated for impairment	372,924	108,327
Total acquired loans	372,924	108,327
Acquired loans | Commercial Real Estate - Construction & Land Development
Allowance for loan losses:
Provision for loan losses before benefit attributable to FDIC loss share agreements	1,628
Benefit attributable to FDIC loss share agreements	(1,319)
Total provision for loan losses charged to operations	309
Provision for loan losses recorded through the FDIC loss share receivable	1,319
Balance at the end of the period	1,628
Loans collectively evaluated for impairment	1,628
Loans:
Loans collectively evaluated for impairment	130,451	51,005
Total acquired loans	130,451	51,005
Acquired loans | Residential Real Estate
Allowance for loan losses:
Balance at the beginning of the period	5,471
Provision for loan losses before benefit attributable to FDIC loss share agreements	(855)	5,471
Benefit attributable to FDIC loss share agreements	813	(5,197)
Total provision for loan losses charged to operations	(42)	274
Provision for loan losses recorded through the FDIC loss share receivable	(813)	5,197
Balance at the end of the period	4,616	5,471
Loans collectively evaluated for impairment	4,616	5,471
Loans:
Loans collectively evaluated for impairment	355,127	128,650
Total acquired loans	355,127	128,650
Acquired loans | Home Equity
Loans:
Loans collectively evaluated for impairment		1,386
Total acquired loans		1,386
Acquired loans | Consumer
Allowance for loan losses:
Provision for loan losses before benefit attributable to FDIC loss share agreements	96
Benefit attributable to FDIC loss share agreements	(88)
Total provision for loan losses charged to operations	8
Provision for loan losses recorded through the FDIC loss share receivable	88
Balance at the end of the period	96
Loans collectively evaluated for impairment	96
Loans:
Loans collectively evaluated for impairment	15,685	10,019
Total acquired loans	15,685	10,019
Acquired loans | Commercial & Industrial
Allowance for loan losses:
Balance at the beginning of the period	4,564
Provision for loan losses before benefit attributable to FDIC loss share agreements	(259)	4,564
Benefit attributable to FDIC loss share agreements	264	(4,336)
Total provision for loan losses charged to operations	5	228
Provision for loan losses recorded through the FDIC loss share receivable	(264)	4,336
Balance at the end of the period	4,305	4,564
Loans collectively evaluated for impairment	4,305	4,564
Loans:
Loans collectively evaluated for impairment	72,884	39,311
Total acquired loans	72,884	39,311
Acquired loans | Single Pay
Allowance for loan losses:
Balance at the beginning of the period	3,561
Provision for loan losses before benefit attributable to FDIC loss share agreements	1,001	3,561
Benefit attributable to FDIC loss share agreements	(951)	(3,383)
Total provision for loan losses charged to operations	50	178
Provision for loan losses recorded through the FDIC loss share receivable	951	3,383
Balance at the end of the period	4,562	3,561
Loans collectively evaluated for impairment	4,562	3,561
Loans:
Loans collectively evaluated for impairment	4,772	4,060
Total acquired loans	4,772	4,060
Acquired loans | FASB ASC Topic 310-20 Loans
Loans:
Loans collectively evaluated for impairment	$ 73,215