Loans and Asset Quality Information (Schedule of Activity in Allowance for Loan Losses for Non-Covered Loans) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Provisions	$ (164)	$ 3,575
Loans receivable:
Ending balance - total	2,394,616	2,446,518	2,395,228
Unamortized net deferred loan costs	783	759	946
Total non-covered loans	2,275,570	2,256,726	2,268,580
Non-covered [Member]
Beginning balance	38,345	44,263	44,263
Charge-offs	(5,360)	(3,468)	(16,288)
Recoveries	681	546	1,546
Transfers from covered category			1,737
Provisions	104	3,365	7,087
Ending balance	33,770	44,706	38,345
Ending balances: Allowance for loan losses
Individually evaluated for impairment	2,741	3,519	2,477
Collectively evaluated for impairment	31,029	41,187	35,868
Loans acquired with deteriorated credit quality
Loans receivable:
Ending balance - total	2,274,787	2,255,967	2,267,634
Unamortized net deferred loan costs	783	759	946
Total non-covered loans	2,275,570	2,256,726	2,268,580
Ending balances: Loans
Individually evaluated for impairment	51,551	46,174	53,531
Collectively evaluated for impairment	2,222,605	2,209,793	2,213,456
Loans acquired with deteriorated credit quality	631		647
Total Non Covered [Member]
Loans receivable:
Total non-covered loans	2,274,787		2,267,634
Commercial, financial and agricultural [Member]
Beginning balance	8,391	7,432	7,432
Charge-offs	(944)	(625)	(4,039)
Recoveries	88	28	140
Transfers from covered category			36
Provisions	(1,778)	2,054	4,822
Ending balance	5,757	8,889	8,391
Ending balances: Allowance for loan losses
Individually evaluated for impairment	131	197	211
Collectively evaluated for impairment	5,626	8,692	8,180
Loans acquired with deteriorated credit quality
Loans receivable:
Ending balance - total	176,013	179,363	160,878
Ending balances: Loans
Individually evaluated for impairment	800	1,093	784
Collectively evaluated for impairment	181,121	183,375	165,944
Loans acquired with deteriorated credit quality
Commercial, financial and agricultural [Member] \| Non-covered [Member]
Loans receivable:
Ending balance - total	181,921	184,468	166,728
Real Estate construction, land development and other land loans [Member]
Beginning balance	6,470	12,966	12,966
Charge-offs	(1,256)	(927)	(2,148)
Recoveries	267	236	398
Transfers from covered category			813
Provisions	525	(3,625)	(5,559)
Ending balance	6,006	8,650	6,470
Ending balances: Allowance for loan losses
Individually evaluated for impairment	415	466	415
Collectively evaluated for impairment	5,591	8,184	6,055
Loans acquired with deteriorated credit quality
Loans receivable:
Ending balance - total	285,319	296,141	288,148
Ending balances: Loans
Individually evaluated for impairment	6,720	7,411	7,991
Collectively evaluated for impairment	250,131	233,899	249,524
Loans acquired with deteriorated credit quality
Real Estate construction, land development and other land loans [Member] \| Non-covered [Member]
Loans receivable:
Ending balance - total	256,851	241,310	257,515
Real estate residential, farmland and mutli-family [Member]
Beginning balance	9,720	15,142	15,142
Charge-offs	(1,569)	(770)	(4,417)
Recoveries	16	65	331
Transfers from covered category			51
Provisions	2,659	(1,704)	(1,387)
Ending balance	10,826	12,733	9,720
Ending balances: Allowance for loan losses
Individually evaluated for impairment	1,690	2,285	1,686
Collectively evaluated for impairment	9,136	10,448	8,034
Loans acquired with deteriorated credit quality
Ending balances: Loans
Individually evaluated for impairment	23,527	21,110	24,010
Collectively evaluated for impairment	815,124	849,244	822,823
Loans acquired with deteriorated credit quality
Real estate residential, farmland and mutli-family [Member] \| Non-covered [Member]
Loans receivable:
Ending balance - total	838,651	870,354	846,833
Total non-covered loans	838,651		846,833
Real estate home equity lines of credit [Member]
Beginning balance	3,731	1,838	1,838
Charge-offs	(67)	(106)	(912)
Recoveries	17	5	45
Transfers from covered category
Provisions	482	1,925	2,760
Ending balance	4,163	3,662	3,731
Ending balances: Allowance for loan losses
Individually evaluated for impairment
Collectively evaluated for impairment	4,163	3,662	3,731
Loans acquired with deteriorated credit quality
Ending balances: Loans
Individually evaluated for impairment		499	476
Collectively evaluated for impairment	199,176	200,358	198,101
Loans acquired with deteriorated credit quality
Real estate home equity lines of credit [Member] \| Non-covered [Member]
Loans receivable:
Ending balance - total	199,176	200,857	198,577
Total non-covered loans	199,176		198,577
Real estate mortgage commercial and other [Member]
Beginning balance	9,045	5,524	5,524
Charge-offs	(923)	(612)	(3,048)
Recoveries	202	95	181
Transfers from covered category			833
Provisions	(2,405)	4,368	5,555
Ending balance	5,919	9,375	9,045
Ending balances: Allowance for loan losses
Individually evaluated for impairment	505	571	165
Collectively evaluated for impairment	5,414	8,804	8,880
Loans acquired with deteriorated credit quality
Loans receivable:
Ending balance - total	885,282	857,327	882,127
Ending balances: Loans
Individually evaluated for impairment	20,504	16,050	20,263
Collectively evaluated for impairment	735,883	696,459	733,875
Loans acquired with deteriorated credit quality	631		647
Real estate mortgage commercial and other [Member] \| Non-covered [Member]
Loans receivable:
Ending balance - total	757,018	712,509	754,785
Consumer [Member]
Beginning balance	841	1,513	1,513
Charge-offs	(601)	(428)	(1,724)
Recoveries	91	117	451
Transfers from covered category			4
Provisions	464	(172)	597
Ending balance	795	1,030	841
Ending balances: Allowance for loan losses
Individually evaluated for impairment
Collectively evaluated for impairment	795	1,030	841
Loans acquired with deteriorated credit quality
Ending balances: Loans
Individually evaluated for impairment		11	7
Collectively evaluated for impairment	41,170	46,458	43,189
Loans acquired with deteriorated credit quality
Consumer [Member] \| Non-covered [Member]
Loans receivable:
Ending balance - total	41,170	46,469	43,196
Total non-covered loans	41,170		43,196
Unallocated [Member]
Beginning balance	147	(152)	(152)
Charge-offs
Recoveries
Transfers from covered category
Provisions	157	519	299
Ending balance	304	367	147
Ending balances: Allowance for loan losses
Individually evaluated for impairment
Collectively evaluated for impairment	304	367	147
Loans acquired with deteriorated credit quality
Ending balances: Loans
Individually evaluated for impairment
Collectively evaluated for impairment
Loans acquired with deteriorated credit quality
Unallocated [Member] \| Non-covered [Member]
Loans receivable:
Ending balance - total

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Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

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