Loans and Leases - Reserve for Loan and Lease Losses and Recorded Investment in Loans and Leases (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Jun. 30, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Dec. 31, 2013
Reserve for loan and lease losses:
Ending balance: individually evaluated for impairment	$ 380			$ 1,142
Ending balance: collectively evaluated for impairment	18,219			20,620
Ending balance: acquired credit impaired loans evaluated for impairment	21
Total ending balance	18,620	$ 19,602	$ 20,662	21,762	$ 24,094	$ 24,494
Loans and leases held for investment:
Ending balance: individually evaluated for impairment	32,768			59,079
Ending balance: collectively evaluated for impairment	1,723,735			1,538,657
Acquired non-credit impaired loans	339,925
Acquired credit impaired loans	1,379
Total Loans and Leases Held for Investment	2,097,807		1,626,625	1,597,736
Commercial, Financial and Agricultural [Member]
Reserve for loan and lease losses:
Ending balance: individually evaluated for impairment	344			685
Ending balance: collectively evaluated for impairment	6,650			6,930
Ending balance: acquired credit impaired loans evaluated for impairment	0
Total ending balance	6,994	6,847	6,920	7,615	9,714	9,789
Loans and leases held for investment:
Ending balance: individually evaluated for impairment	13,932			18,214
Ending balance: collectively evaluated for impairment	441,537			420,342
Acquired non-credit impaired loans	27,562
Acquired credit impaired loans	311
Total Loans and Leases Held for Investment	483,342		457,827	438,556
Real Estate-Commercial and Construction [Member]
Reserve for loan and lease losses:
Ending balance: individually evaluated for impairment	0			27
Ending balance: collectively evaluated for impairment	6,903			9,061
Ending balance: acquired credit impaired loans evaluated for impairment	8
Total ending balance	6,911	7,801	8,943	9,088	9,263	8,780
Loans and leases held for investment:
Ending balance: individually evaluated for impairment	13,622			37,341
Ending balance: collectively evaluated for impairment	768,518			675,817
Acquired non-credit impaired loans	157,866
Acquired credit impaired loans	512
Total Loans and Leases Held for Investment	940,518			713,158
Real Estate-Residential Secured for Business Purpose [Member]
Reserve for loan and lease losses:
Ending balance: individually evaluated for impairment	0			430
Ending balance: collectively evaluated for impairment	493			530
Ending balance: acquired credit impaired loans evaluated for impairment	13
Total ending balance	506	616	763	960	1,025	1,062
Loans and leases held for investment:
Ending balance: individually evaluated for impairment	4,278			2,921
Ending balance: collectively evaluated for impairment	61,093			32,446
Acquired non-credit impaired loans	138,100
Acquired credit impaired loans	493
Total Loans and Leases Held for Investment	203,964		36,932	35,367
Real Estate-Residential and Home Equity Secured for Personal Purpose [Member]
Reserve for loan and lease losses:
Ending balance: individually evaluated for impairment	36			0
Ending balance: collectively evaluated for impairment	1,147			1,178
Ending balance: acquired credit impaired loans evaluated for impairment	0
Total ending balance	1,183	1,188	1,124	1,178	1,248	1,284
Loans and leases held for investment:
Ending balance: individually evaluated for impairment	936			603
Ending balance: collectively evaluated for impairment	298,128			267,956
Acquired non-credit impaired loans	16,055
Acquired credit impaired loans	63
Total Loans and Leases Held for Investment	315,182			268,559
Loans to Individuals [Member]
Reserve for loan and lease losses:
Ending balance: individually evaluated for impairment	0			0
Ending balance: collectively evaluated for impairment	415			332
Ending balance: acquired credit impaired loans evaluated for impairment	0
Total ending balance	415	389	360	332	405	694
Loans and leases held for investment:
Ending balance: individually evaluated for impairment	0			0
Ending balance: collectively evaluated for impairment	29,575			30,144
Acquired non-credit impaired loans	342
Acquired credit impaired loans	0
Total Loans and Leases Held for Investment	29,917		29,941	30,144
Lease Financings [Member]
Reserve for loan and lease losses:
Ending balance: individually evaluated for impairment	0			0
Ending balance: collectively evaluated for impairment	999			1,115
Ending balance: acquired credit impaired loans evaluated for impairment	0
Total ending balance	999	1,125	985	1,115	1,101	1,285
Loans and leases held for investment:
Ending balance: individually evaluated for impairment	0			0
Ending balance: collectively evaluated for impairment	124,884			111,952
Acquired non-credit impaired loans	0
Acquired credit impaired loans	0
Total Loans and Leases Held for Investment	124,884		118,460	111,952
Unallocated Financing Receivables [Member]
Reserve for loan and lease losses:
Ending balance: collectively evaluated for impairment	1,612			1,474
Ending balance: acquired credit impaired loans evaluated for impairment	0
Total ending balance	$ 1,612	$ 1,636	$ 1,567	$ 1,474	$ 1,338	$ 1,600