Loans and Allowance for Loan Losses (Details 9) (Acquired loans, USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012
Loans and Allowance for Loan Losses
Total covered loans	$ 257,066	$ 282,728	$ 363,051
Non-covered loans	738,189	792,014	6,093
Commercial Loans Greater Than or Equal to $1 Million-CBT
Loans and Allowance for Loan Losses
Total covered loans	48,110	49,684	56,316
Commercial Loans Greater Than or Equal to $1 Million-CBT | Pass
Loans and Allowance for Loan Losses
Total covered loans	14,505	143,555	15,947
Commercial Loans Greater Than or Equal to $1 Million-CBT | Special mention
Loans and Allowance for Loan Losses
Total covered loans	3,476	3,470	4,665
Commercial Loans Greater Than or Equal to $1 Million-CBT | Substandard
Loans and Allowance for Loan Losses
Total covered loans	30,129	31,859	35,704
Commercial real estate
Loans and Allowance for Loan Losses
Total covered loans	52,972	62,962	99,834
Non-covered loans	294,266	309,962	963
Commercial real estate | Pass
Loans and Allowance for Loan Losses
Total covered loans	21,208	22,687	31,213
Non-covered loans	162,681	274,721	923
Commercial real estate | Special mention
Loans and Allowance for Loan Losses
Total covered loans	10,078	10,609	21,412
Non-covered loans	51,828	11,670	40
Commercial real estate | Substandard
Loans and Allowance for Loan Losses
Total covered loans	21,539	29,501	46,774
Non-covered loans	79,757	23,571
Commercial real estate | Doubtful
Loans and Allowance for Loan Losses
Total covered loans	147	165	435
Commercial Real Estate - Construction and Development
Loans and Allowance for Loan Losses
Total covered loans	27,657	32,575	44,256
Non-covered loans	82,402	97,876	83
Commercial Real Estate - Construction and Development | Pass
Loans and Allowance for Loan Losses
Total covered loans	7,042	7,134	9,168
Non-covered loans	30,563	80,008	79
Commercial Real Estate - Construction and Development | Special mention
Loans and Allowance for Loan Losses
Total covered loans	2,702	3,474	7,079
Non-covered loans	16,293	4,268
Commercial Real Estate - Construction and Development | Substandard
Loans and Allowance for Loan Losses
Total covered loans	17,168	21,154	25,331
Non-covered loans	35,398	13,600	4
Commercial Real Estate - Construction and Development | Doubtful
Loans and Allowance for Loan Losses
Total covered loans	745	813	2,678
Non-covered loans	148
Residential Real Estate
Loans and Allowance for Loan Losses
Total covered loans	97,772	104,811	128,210
Non-covered loans	238,258	250,316	979
Residential Real Estate | Pass
Loans and Allowance for Loan Losses
Total covered loans	37,403	41,907	48,349
Non-covered loans	147,347	213,069	766
Residential Real Estate | Special mention
Loans and Allowance for Loan Losses
Total covered loans	18,984	20,915	25,117
Non-covered loans	32,752	17,324
Residential Real Estate | Substandard
Loans and Allowance for Loan Losses
Total covered loans	40,990	41,963	51,572
Non-covered loans	58,074	19,923	213
Residential Real Estate | Doubtful
Loans and Allowance for Loan Losses
Total covered loans	395	26	3,172
Non-covered loans	85
Consumer
Loans and Allowance for Loan Losses
Total covered loans	3,845	4,324	6,145
Non-covered loans	9,323	11,361	2,438
Consumer | Pass
Loans and Allowance for Loan Losses
Total covered loans	1,912	2,215	2,797
Non-covered loans	8,302	10,712	1,920
Consumer | Special mention
Loans and Allowance for Loan Losses
Total covered loans	536	574	764
Non-covered loans	398	209	160
Consumer | Substandard
Loans and Allowance for Loan Losses
Total covered loans	1,397	1,534	2,317
Non-covered loans	623	440	358
Consumer | Doubtful
Loans and Allowance for Loan Losses
Total covered loans		1	267
Commercial & Industrial
Loans and Allowance for Loan Losses
Total covered loans	21,978	23,600	22,890
Non-covered loans	43,706	49,284	1,630
Commercial & Industrial | Pass
Loans and Allowance for Loan Losses
Total covered loans	7,710	8,073	6,552
Non-covered loans	32,419	45,973	1,027
Commercial & Industrial | Special mention
Loans and Allowance for Loan Losses
Total covered loans	3,816	3,744	4,529
Non-covered loans	6,940	1,549	515
Commercial & Industrial | Substandard
Loans and Allowance for Loan Losses
Total covered loans	10,422	11,753	11,242
Non-covered loans	4,347	1,762	88
Commercial & Industrial | Doubtful
Loans and Allowance for Loan Losses
Total covered loans	30	30	567
Single Pay
Loans and Allowance for Loan Losses
Total covered loans	4,732	4,772	5,400
Single Pay | Pass
Loans and Allowance for Loan Losses
Total covered loans	60	57	730
Single Pay | Special mention
Loans and Allowance for Loan Losses
Total covered loans	51	52	56
Single Pay | Substandard
Loans and Allowance for Loan Losses
Total covered loans	4,621	4,663	4,614
FASB ASC Topic 310-20 Loans
Loans and Allowance for Loan Losses
Non-covered loans	70,234	73,215
FASB ASC Topic 310-20 Loans | Pass
Loans and Allowance for Loan Losses
Non-covered loans	52,840	71,174
FASB ASC Topic 310-20 Loans | Special mention
Loans and Allowance for Loan Losses
Non-covered loans	10,877	574
FASB ASC Topic 310-20 Loans | Substandard
Loans and Allowance for Loan Losses
Non-covered loans	$ 6,517	$ 1,467