Loans and Leases - Reserve for Loan and Lease Losses and Recorded Investment in Loans and Leases (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013
Reserve for loan and lease losses:
Ending balance: individually evaluated for impairment	$ 444
Ending balance: collectively evaluated for impairment	19,158
Total ending balance	19,602
Ending balance: individually evaluated for impairment				$ 1,144
Ending balance: collectively evaluated for impairment				22,950
Total ending balance	19,602	$ 20,934	$ 20,662	24,094	$ 24,567	$ 24,494
Loans and leases held for investment:
Ending balance: individually evaluated for impairment	38,947
Ending balance: collectively evaluated for impairment	1,712,611
Total ending balance	1,751,558		1,626,625
Ending balance: individually evaluated for impairment				52,424
Ending balance: collectively evaluated for impairment				1,534,570
Total Loans and Leases Held for Investment	2,107,857		1,626,625	1,586,994
Commercial, Financial and Agricultural [Member]
Reserve for loan and lease losses:
Ending balance: individually evaluated for impairment	444
Ending balance: collectively evaluated for impairment	6,403
Total ending balance	6,847
Ending balance: individually evaluated for impairment				680
Ending balance: collectively evaluated for impairment				9,034
Total ending balance	6,847	6,712	6,920	9,714	9,547	9,789
Loans and leases held for investment:
Ending balance: individually evaluated for impairment	15,409
Ending balance: collectively evaluated for impairment	469,367
Total ending balance	484,776		457,827
Ending balance: individually evaluated for impairment				14,800
Ending balance: collectively evaluated for impairment				433,193
Total Loans and Leases Held for Investment	511,960		457,827	447,993
Real Estate-Commercial and Construction [Member]
Reserve for loan and lease losses:
Ending balance: individually evaluated for impairment	0
Ending balance: collectively evaluated for impairment	7,801
Total ending balance	7,801
Ending balance: individually evaluated for impairment				8
Ending balance: collectively evaluated for impairment				9,255
Total ending balance	7,801	9,648	8,943	9,263	9,247	8,780
Loans and leases held for investment:
Ending balance: individually evaluated for impairment	18,956
Ending balance: collectively evaluated for impairment	758,024
Total ending balance	776,980
Ending balance: individually evaluated for impairment				34,259
Ending balance: collectively evaluated for impairment				668,536
Total Loans and Leases Held for Investment				702,795
Real Estate-Residential Secured for Business Purpose [Member]
Reserve for loan and lease losses:
Ending balance: individually evaluated for impairment	0
Ending balance: collectively evaluated for impairment	616
Total ending balance	616
Ending balance: individually evaluated for impairment				456
Ending balance: collectively evaluated for impairment				569
Total ending balance	616	668	763	1,025	1,056	1,062
Loans and leases held for investment:
Ending balance: individually evaluated for impairment	3,633
Ending balance: collectively evaluated for impairment	48,290
Total ending balance	51,923		36,932
Ending balance: individually evaluated for impairment				2,477
Ending balance: collectively evaluated for impairment				32,807
Total Loans and Leases Held for Investment	187,894		36,932	35,284
Real Estate-Residential and Home Equity Secured for Personal Purpose [Member]
Reserve for loan and lease losses:
Ending balance: individually evaluated for impairment	0
Ending balance: collectively evaluated for impairment	1,188
Total ending balance	1,188
Ending balance: individually evaluated for impairment				0
Ending balance: collectively evaluated for impairment				1,248
Total ending balance	1,188	1,128	1,124	1,248	1,221	1,284
Loans and leases held for investment:
Ending balance: individually evaluated for impairment	949
Ending balance: collectively evaluated for impairment	288,263
Total ending balance	289,212
Ending balance: individually evaluated for impairment				887
Ending balance: collectively evaluated for impairment				260,345
Total Loans and Leases Held for Investment				261,232
Loans to Individuals [Member]
Reserve for loan and lease losses:
Ending balance: individually evaluated for impairment	0
Ending balance: collectively evaluated for impairment	389
Total ending balance	389
Ending balance: individually evaluated for impairment				0
Ending balance: collectively evaluated for impairment				405
Total ending balance	389	365	360	405	598	694
Loans and leases held for investment:
Ending balance: individually evaluated for impairment	0
Ending balance: collectively evaluated for impairment	28,070
Total ending balance	28,070		29,941
Ending balance: individually evaluated for impairment				1
Ending balance: collectively evaluated for impairment				31,563
Total Loans and Leases Held for Investment	28,415		29,941	31,564
Lease Financings [Member]
Reserve for loan and lease losses:
Ending balance: individually evaluated for impairment	0
Ending balance: collectively evaluated for impairment	1,125
Total ending balance	1,125
Ending balance: individually evaluated for impairment				0
Ending balance: collectively evaluated for impairment				1,101
Total ending balance	1,125	1,013	985	1,101	1,295	1,285
Loans and leases held for investment:
Ending balance: individually evaluated for impairment	0
Ending balance: collectively evaluated for impairment	120,597
Total ending balance	120,597		118,460
Ending balance: individually evaluated for impairment				0
Ending balance: collectively evaluated for impairment				108,126
Total Loans and Leases Held for Investment	120,597		118,460	108,126
Unallocated Financing Receivables [Member]
Reserve for loan and lease losses:
Ending balance: collectively evaluated for impairment	1,636
Total ending balance	1,636
Ending balance: collectively evaluated for impairment				1,338
Total ending balance	$ 1,636	$ 1,400	$ 1,567	$ 1,338	$ 1,603	$ 1,600