Loans and Allowance for Loan Losses (Details 9) (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 & development
Loans and Allowance for Loan Losses
Total acquired loans	132,176		58,317
Commercial & 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
Commercial Real Estate
Loans and Allowance for Loan Losses
Total acquired loans	477,968		151,444
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
Total acquired loans	1,665,333	73,215
FASB ASC Topic 310-20 | Construction & development
Loans and Allowance for Loan Losses
Total acquired loans	55,259	839
FASB ASC Topic 310-20 | Construction & development | Pass
Loans and Allowance for Loan Losses
Total acquired loans	54,863	796
FASB ASC Topic 310-20 | Construction & development | Substandard
Loans and Allowance for Loan Losses
Total acquired loans	396	43
FASB ASC Topic 310-20 | Commercial Non-owner Occupied
Loans and Allowance for Loan Losses
Total acquired loans	65,181	2,877
FASB ASC Topic 310-20 | Commercial Non-owner Occupied | Pass
Loans and Allowance for Loan Losses
Total acquired loans	63,362	2,877
FASB ASC Topic 310-20 | Commercial Non-owner Occupied | Special mention
Loans and Allowance for Loan Losses
Total acquired loans	1,332
FASB ASC Topic 310-20 | Commercial Non-owner Occupied | Substandard
Loans and Allowance for Loan Losses
Total acquired loans	487
FASB ASC Topic 310-20 | Commercial Owner Occupied
Loans and Allowance for Loan Losses
Total acquired loans	83,133	12,141
FASB ASC Topic 310-20 | Commercial Owner Occupied | Pass
Loans and Allowance for Loan Losses
Total acquired loans	81,973	11,977
FASB ASC Topic 310-20 | Commercial Owner Occupied | Special mention
Loans and Allowance for Loan Losses
Total acquired loans	325	164
FASB ASC Topic 310-20 | Commercial Owner Occupied | Substandard
Loans and Allowance for Loan Losses
Total acquired loans	835
FASB ASC Topic 310-20 | Commercial & Industrial
Loans and Allowance for Loan Losses
Total acquired loans	64,069	17,531
FASB ASC Topic 310-20 | Commercial & Industrial | Pass
Loans and Allowance for Loan Losses
Total acquired loans	61,025	17,515
FASB ASC Topic 310-20 | Commercial & Industrial | Special mention
Loans and Allowance for Loan Losses
Total acquired loans	2,280
FASB ASC Topic 310-20 | Commercial & Industrial | Substandard
Loans and Allowance for Loan Losses
Total acquired loans	764	16
FASB ASC Topic 310-20 | Other Income Producing Property
Loans and Allowance for Loan Losses
Total acquired loans	78,344	3,688
FASB ASC Topic 310-20 | Other Income Producing Property | Pass
Loans and Allowance for Loan Losses
Total acquired loans	75,624	3,352
FASB ASC Topic 310-20 | Other Income Producing Property | Special mention
Loans and Allowance for Loan Losses
Total acquired loans	1,869	244
FASB ASC Topic 310-20 | Other Income Producing Property | Substandard
Loans and Allowance for Loan Losses
Total acquired loans	851	92
FASB ASC Topic 310-20 | Consumer Owner Occupied
Loans and Allowance for Loan Losses
Total acquired loans	769,086
FASB ASC Topic 310-20 | Consumer Owner Occupied | Pass
Loans and Allowance for Loan Losses
Total acquired loans	767,359
FASB ASC Topic 310-20 | Consumer Owner Occupied | Special mention
Loans and Allowance for Loan Losses
Total acquired loans	425
FASB ASC Topic 310-20 | Consumer Owner Occupied | Substandard
Loans and Allowance for Loan Losses
Total acquired loans	1,302
FASB ASC Topic 310-20 | Home Equity
Loans and Allowance for Loan Losses
Total acquired loans	274,893	36,139
FASB ASC Topic 310-20 | Home Equity | Pass
Loans and Allowance for Loan Losses
Total acquired loans	257,630	34,656
FASB ASC Topic 310-20 | Home Equity | Special mention
Loans and Allowance for Loan Losses
Total acquired loans	6,517	167
FASB ASC Topic 310-20 | Home Equity | Substandard
Loans and Allowance for Loan Losses
Total acquired loans	10,746	1,316
FASB ASC Topic 310-20 | Consumer
Loans and Allowance for Loan Losses
Total acquired loans	275,368
FASB ASC Topic 310-20 | Consumer | Pass
Loans and Allowance for Loan Losses
Total acquired loans	275,188
FASB ASC Topic 310-20 | Consumer | Special mention
Loans and Allowance for Loan Losses
Total acquired loans	106
FASB ASC Topic 310-20 | Consumer | Substandard
Loans and Allowance for Loan Losses
Total acquired loans	75
FASB ASC Topic 310-30
Loans and Allowance for Loan Losses
Total acquired loans	1,347,770	1,001,527	520,991
FASB ASC Topic 310-30 | Construction & development
Loans and Allowance for Loan Losses
Total acquired loans	132,176	130,451	58,317
FASB ASC Topic 310-30 | Construction & development | Pass
Loans and Allowance for Loan Losses
Total acquired loans	41,801	87,142	21,351
FASB ASC Topic 310-30 | Construction & development | Special mention
Loans and Allowance for Loan Losses
Total acquired loans	19,711	7,742	7,081
FASB ASC Topic 310-30 | Construction & development | Substandard
Loans and Allowance for Loan Losses
Total acquired loans	70,664	34,754	28,391
FASB ASC Topic 310-30 | Construction & development | Doubtful
Loans and Allowance for Loan Losses
Total acquired loans		813	1,494
FASB ASC Topic 310-30 | Commercial & Industrial
Loans and Allowance for Loan Losses
Total acquired loans	81,734	72,884	37,499
FASB ASC Topic 310-30 | Commercial & Industrial | Pass
Loans and Allowance for Loan Losses
Total acquired loans	41,320	54,046	17,044
FASB ASC Topic 310-30 | Commercial & Industrial | Special mention
Loans and Allowance for Loan Losses
Total acquired loans	4,285	5,293	5,281
FASB ASC Topic 310-30 | Commercial & Industrial | Substandard
Loans and Allowance for Loan Losses
Total acquired loans	36,129	13,515	15,119
FASB ASC Topic 310-30 | Commercial & Industrial | Doubtful
Loans and Allowance for Loan Losses
Total acquired loans		30	55
FASB ASC Topic 310-30 | Consumer
Loans and Allowance for Loan Losses
Total acquired loans	108,420	15,685	10,125
FASB ASC Topic 310-30 | Consumer | Pass
Loans and Allowance for Loan Losses
Total acquired loans	8,639	12,927	7,136
FASB ASC Topic 310-30 | Consumer | Special mention
Loans and Allowance for Loan Losses
Total acquired loans	40,038	783	959
FASB ASC Topic 310-30 | Consumer | Substandard
Loans and Allowance for Loan Losses
Total acquired loans	59,743	1,974	1,997
FASB ASC Topic 310-30 | Consumer | Doubtful
Loans and Allowance for Loan Losses
Total acquired loans		1	33
FASB ASC Topic 310-30 | Commercial Loans Greater Than or Equal to $1 Million-CBT
Loans and Allowance for Loan Losses
Total acquired loans	37,894	49,684	53,301
FASB ASC Topic 310-30 | Commercial Loans Greater Than or Equal to $1 Million-CBT | Pass
Loans and Allowance for Loan Losses
Total acquired loans	15,417	14,355	15,854
FASB ASC Topic 310-30 | Commercial Loans Greater Than or Equal to $1 Million-CBT | Special mention
Loans and Allowance for Loan Losses
Total acquired loans	2,635	3,470	3,462
FASB ASC Topic 310-30 | Commercial Loans Greater Than or Equal to $1 Million-CBT | Substandard
Loans and Allowance for Loan Losses
Total acquired loans	19,842	31,859	33,985
FASB ASC Topic 310-30 | Commercial Real Estate
Loans and Allowance for Loan Losses
Total acquired loans	477,968	372,924	74,757
FASB ASC Topic 310-30 | Commercial Real Estate | Pass
Loans and Allowance for Loan Losses
Total acquired loans	220,307	297,408	24,992
FASB ASC Topic 310-30 | Commercial Real Estate | Special mention
Loans and Allowance for Loan Losses
Total acquired loans	69,406	22,279	12,505
FASB ASC Topic 310-30 | Commercial Real Estate | Substandard
Loans and Allowance for Loan Losses
Total acquired loans	188,255	53,072	37,095
FASB ASC Topic 310-30 | Commercial Real Estate | Doubtful
Loans and Allowance for Loan Losses
Total acquired loans		165	165
FASB ASC Topic 310-30 | Residential real estate
Loans and Allowance for Loan Losses
Total acquired loans	505,127	355,127	205,441
FASB ASC Topic 310-30 | Residential real estate | Pass
Loans and Allowance for Loan Losses
Total acquired loans	208,135	254,976	127,274
FASB ASC Topic 310-30 | Residential real estate | Special mention
Loans and Allowance for Loan Losses
Total acquired loans	93,623	38,239	27,322
FASB ASC Topic 310-30 | Residential real estate | Substandard
Loans and Allowance for Loan Losses
Total acquired loans	203,267	61,886	50,412
FASB ASC Topic 310-30 | Residential real estate | Doubtful
Loans and Allowance for Loan Losses
Total acquired loans	102	26	433
FASB ASC Topic 310-30 | Single pay
Loans and Allowance for Loan Losses
Total acquired loans	4,451	4,772	4,864
FASB ASC Topic 310-30 | Single pay | Pass
Loans and Allowance for Loan Losses
Total acquired loans	46	57	1,881
FASB ASC Topic 310-30 | Single pay | Special mention
Loans and Allowance for Loan Losses
Total acquired loans		52	52
FASB ASC Topic 310-30 | Single pay | Substandard
Loans and Allowance for Loan Losses
Total acquired loans	$ 4,405	$ 4,663	$ 2,931