Loans and Allowance for Loan Losses (Details 11) (Acquired loans, USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2012
Loans and Allowance for Loan Losses
Total acquired loans	$ 3,013,103	$ 1,074,742	$ 520,991
Construction and land development
Loans and Allowance for Loan Losses
Total acquired loans	132,176		58,317
Commercial and industrial
Loans and Allowance for Loan Losses
Total acquired loans	81,734		37,499
Consumer
Loans and Allowance for Loan Losses
Total acquired loans	108,420		10,125
Commercial Loans Greater Than or Equal to $1 Million-CBT
Loans and Allowance for Loan Losses
Total acquired loans	37,894		53,301
Residential real estate
Loans and Allowance for Loan Losses
Total acquired loans	505,127		205,441
Single pay
Loans and Allowance for Loan Losses
Total acquired loans	4,451		4,864
FASB ASC Topic 310-20
Loans and Allowance for Loan Losses
30-59 Days Past Due	3,581	388
60-89 Days Past Due	1,367	111
90+ Days Past Due	1,005	148
Total Past Due	5,953	647
Current	1,659,380	72,568
Total acquired loans	1,665,333	73,215
FASB ASC Topic 310-20 | Construction and land development
Loans and Allowance for Loan Losses
60-89 Days Past Due	78
90+ Days Past Due	409	43
Total Past Due	487	43
Current	54,772	796
Total acquired loans	55,259	839
FASB ASC Topic 310-20 | Commercial non-owner occupied
Loans and Allowance for Loan Losses
30-59 Days Past Due	17
Total Past Due	17
Current	65,164	2,877
Total acquired loans	65,181	2,877
FASB ASC Topic 310-20 | Commercial owner occupied
Loans and Allowance for Loan Losses
30-59 Days Past Due	1,250
90+ Days Past Due	62
Total Past Due	1,312
Current	81,821	12,141
Total acquired loans	83,133	12,141
FASB ASC Topic 310-20 | Consumer owner occupied
Loans and Allowance for Loan Losses
30-59 Days Past Due	26
60-89 Days Past Due	714
Total Past Due	740
Current	768,346
Total acquired loans	769,086
FASB ASC Topic 310-20 | Home equity loans
Loans and Allowance for Loan Losses
30-59 Days Past Due	1,262	242
60-89 Days Past Due	483	111
90+ Days Past Due	309	105
Total Past Due	2,054	458
Current	272,839	35,681
Total acquired loans	274,893	36,139
FASB ASC Topic 310-20 | Commercial and industrial
Loans and Allowance for Loan Losses
30-59 Days Past Due	381	11
90+ Days Past Due	147
Total Past Due	528	11
Current	63,541	17,520
Total acquired loans	64,069	17,531
FASB ASC Topic 310-20 | Other income producing property
Loans and Allowance for Loan Losses
30-59 Days Past Due	414	135
Total Past Due	414	135
Current	77,930	3,553
Total acquired loans	78,344	3,688
FASB ASC Topic 310-20 | Consumer
Loans and Allowance for Loan Losses
30-59 Days Past Due	231
60-89 Days Past Due	92
90+ Days Past Due	78
Total Past Due	401
Current	274,967
Total acquired loans	275,368
FASB ASC Topic 310-20 | Commercial Real Estate
Loans and Allowance for Loan Losses
Total acquired loans	1,043,979	36,139
FASB ASC Topic 310-30
Loans and Allowance for Loan Losses
30-59 Days Past Due	28,833	18,825	15,314
60-89 Days Past Due	9,548	13,320	3,118
90+ Days Past Due	96,414	82,937	71,286
Total Past Due	134,795	115,082	89,718
Current	1,212,975	886,445	431,273
Total acquired loans	1,347,770	1,001,527	520,991
FASB ASC Topic 310-30 | Construction and land development
Loans and Allowance for Loan Losses
30-59 Days Past Due	2,625	2,976	2,824
60-89 Days Past Due	678	1,573	919
90+ Days Past Due	19,011	18,718	14,227
Total Past Due	22,314	23,267	17,970
Current	109,862	107,184	40,347
Total acquired loans	132,176	130,451	58,317
FASB ASC Topic 310-30 | Commercial and industrial
Loans and Allowance for Loan Losses
30-59 Days Past Due	1,460	1,268	755
60-89 Days Past Due	954	287	478
90+ Days Past Due	4,981	5,147	5,132
Total Past Due	7,395	6,702	6,365
Current	74,339	66,182	31,134
Total acquired loans	81,734	72,884	37,499
FASB ASC Topic 310-30 | Consumer
Loans and Allowance for Loan Losses
30-59 Days Past Due	1,754	181	173
60-89 Days Past Due	478	76	100
90+ Days Past Due	2,036	736	836
Total Past Due	4,268	993	1,109
Current	104,152	14,692	9,016
Total acquired loans	108,420	15,685	10,125
FASB ASC Topic 310-30 | Commercial Loans Greater Than or Equal to $1 Million-CBT
Loans and Allowance for Loan Losses
30-59 Days Past Due		922	3,174
60-89 Days Past Due	787	993
90+ Days Past Due	13,210	22,471	21,638
Total Past Due	13,997	24,386	24,812
Current	23,897	25,298	28,489
Total acquired loans	37,894	49,684	53,301
FASB ASC Topic 310-30 | Commercial Real Estate
Loans and Allowance for Loan Losses
30-59 Days Past Due	11,992	5,866	4,290
60-89 Days Past Due	2,552	2,306	487
90+ Days Past Due	29,451	17,488	15,846
Total Past Due	43,995	25,660	20,623
Current	433,973	347,264	130,821
Total acquired loans	477,968	372,924	151,444
FASB ASC Topic 310-30 | Residential real estate
Loans and Allowance for Loan Losses
30-59 Days Past Due	11,002	7,611	4,097
60-89 Days Past Due	4,081	4,829	1,131
90+ Days Past Due	27,703	18,315	13,337
Total Past Due	42,786	30,755	18,565
Current	462,341	324,372	186,876
Total acquired loans	505,127	355,127	205,441
FASB ASC Topic 310-30 | Single pay
Loans and Allowance for Loan Losses
30-59 Days Past Due		1	1
60-89 Days Past Due	18	3,256	3
90+ Days Past Due	22	62	270
Total Past Due	40	3,319	274
Current	4,411	1,453	4,590
Total acquired loans	$ 4,451	$ 4,772	$ 4,864