Loans and Allowance for Loan Losses (Details 9) (Acquired loans, USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Loans and Allowance for Loan Losses
Total covered loans	$ 282,728	$ 394,495
Non-covered loans	792,014	7,706
Commercial Loans Greater Than or Equal to $1 Million-CBT
Loans and Allowance for Loan Losses
Total covered loans	49,684	60,829
Commercial Loans Greater Than or Equal to $1 Million-CBT | Pass
Loans and Allowance for Loan Losses
Total covered loans	14,355	17,257
Commercial Loans Greater Than or Equal to $1 Million-CBT | Special mention
Loans and Allowance for Loan Losses
Total covered loans	3,470	5,164
Commercial Loans Greater Than or Equal to $1 Million-CBT | Substandard
Loans and Allowance for Loan Losses
Total covered loans	31,859	38,408
Commercial real estate
Loans and Allowance for Loan Losses
Total covered loans	62,962	107,465
Non-covered loans	309,962	862
Commercial real estate | Pass
Loans and Allowance for Loan Losses
Total covered loans	22,687	33,770
Non-covered loans	274,721	799
Commercial real estate | Special mention
Loans and Allowance for Loan Losses
Total covered loans	10,609	22,089
Non-covered loans	11,670	38
Commercial real estate | Substandard
Loans and Allowance for Loan Losses
Total covered loans	29,501	51,108
Non-covered loans	23,571	25
Commercial real estate | Doubtful
Loans and Allowance for Loan Losses
Total covered loans	165	498
Commercial Real Estate - Construction & Land Development
Loans and Allowance for Loan Losses
Total covered loans	32,575	50,953
Non-covered loans	97,876	52
Commercial Real Estate - Construction & Land Development | Pass
Loans and Allowance for Loan Losses
Total covered loans	7,134	11,791
Non-covered loans	80,008	47
Commercial Real Estate - Construction & Land Development | Special mention
Loans and Allowance for Loan Losses
Total covered loans	3,474	5,947
Non-covered loans	4,268
Commercial Real Estate - Construction & Land Development | Substandard
Loans and Allowance for Loan Losses
Total covered loans	21,154	30,566
Non-covered loans	13,600	5
Commercial Real Estate - Construction & Land Development | Doubtful
Loans and Allowance for Loan Losses
Total covered loans	813	2,649
Residential Real Estate
Loans and Allowance for Loan Losses
Total covered loans	104,811	127,658
Non-covered loans	250,316	997
Residential Real Estate | Pass
Loans and Allowance for Loan Losses
Total covered loans	41,907	50,976
Non-covered loans	213,069	777
Residential Real Estate | Special mention
Loans and Allowance for Loan Losses
Total covered loans	20,915	19,550
Non-covered loans	17,324	22
Residential Real Estate | Substandard
Loans and Allowance for Loan Losses
Total covered loans	41,963	54,281
Non-covered loans	19,923	220
Residential Real Estate | Doubtful
Loans and Allowance for Loan Losses
Total covered loans	26	2,851
Consumer
Loans and Allowance for Loan Losses
Total covered loans	4,324	7,033
Non-covered loans	11,361	2,986
Consumer | Pass
Loans and Allowance for Loan Losses
Total covered loans	2,215	3,375
Non-covered loans	10,712	2,394
Consumer | Special mention
Loans and Allowance for Loan Losses
Total covered loans	574	722
Non-covered loans	209	168
Consumer | Substandard
Loans and Allowance for Loan Losses
Total covered loans	1,534	2,446
Non-covered loans	440	424
Consumer | Doubtful
Loans and Allowance for Loan Losses
Total covered loans	1	490
Commercial & Industrial
Loans and Allowance for Loan Losses
Total covered loans	23,600	36,502
Non-covered loans	49,284	2,809
Commercial & Industrial | Pass
Loans and Allowance for Loan Losses
Total covered loans	8,073	9,007
Non-covered loans	45,973	2,201
Commercial & Industrial | Special mention
Loans and Allowance for Loan Losses
Total covered loans	3,744	6,963
Non-covered loans	1,549	332
Commercial & Industrial | Substandard
Loans and Allowance for Loan Losses
Total covered loans	11,753	19,476
Non-covered loans	1,762	276
Commercial & Industrial | Doubtful
Loans and Allowance for Loan Losses
Total covered loans	30	1,056
Single Pay
Loans and Allowance for Loan Losses
Total covered loans	4,772	4,060
Single Pay | Pass
Loans and Allowance for Loan Losses
Total covered loans	57	465
Single Pay | Special mention
Loans and Allowance for Loan Losses
Total covered loans	52	62
Single Pay | Substandard
Loans and Allowance for Loan Losses
Total covered loans	4,633	3,533
FASB ASC Topic 310-20 Loans
Loans and Allowance for Loan Losses
Non-covered loans	73,215
FASB ASC Topic 310-20 Loans | Pass
Loans and Allowance for Loan Losses
Non-covered loans	71,174
FASB ASC Topic 310-20 Loans | Special mention
Loans and Allowance for Loan Losses
Non-covered loans	574
FASB ASC Topic 310-20 Loans | Substandard
Loans and Allowance for Loan Losses
Non-covered loans	$ 1,467