Loans and Leases - Reserve for Loan and Lease Losses Roll Forward (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	$ 19,528	$ 16,452	$ 17,499	$ 17,628
Charge-offs	(1,718)	(830)	(2,415)	(2,902)
Recoveries	334	701	615	1,271
Provision (recovery of provision)	2,767	653	5,209	980
Provision for acquired credit impaired loans	(1)	177	2	176
Ending balance	20,910	17,153	20,910	17,153
Commercial, Financial and Agricultural [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	7,890	5,630	7,037	6,418
Charge-offs	(108)	(346)	(286)	(1,827)
Recoveries	210	515	397	965
Provision (recovery of provision)	321	(11)	1,165	232
Provision for acquired credit impaired loans	0	0	0	0
Ending balance	8,313	5,788	8,313	5,788
Real Estate-Commercial and Construction [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	7,624	6,471	7,505	6,572
Charge-offs	(30)	(179)	(30)	(205)
Recoveries	0	9	3	16
Provision (recovery of provision)	874	1,070	990	988
Provision for acquired credit impaired loans	0	178	0	178
Ending balance	8,468	7,549	8,468	7,549
Real Estate-Residential Secured for Business Purpose [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	1,345	747	774	763
Charge-offs	(1,139)	(27)	(1,181)	(265)
Recoveries	8	34	18	53
Provision (recovery of provision)	915	(698)	1,518	(495)
Provision for acquired credit impaired loans	0	0	0	0
Ending balance	1,129	56	1,129	56
Real Estate-Residential and Home Equity Secured for Personal Purpose [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	1,001	1,312	993	1,575
Charge-offs	0	(10)	(94)	(56)
Recoveries	4	34	21	51
Provision (recovery of provision)	(30)	(34)	52	(267)
Provision for acquired credit impaired loans	(1)	(1)	2	(2)
Ending balance	974	1,301	974	1,301
Loans to Individuals [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	335	356	364	346
Charge-offs	(114)	(108)	(240)	(184)
Recoveries	46	30	81	63
Provision (recovery of provision)	62	133	124	186
Provision for acquired credit impaired loans	0	0	0	0
Ending balance	329	411	329	411
Lease Financings [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	1,329	922	788	1,042
Charge-offs	(327)	(160)	(584)	(365)
Recoveries	66	79	95	123
Provision (recovery of provision)	592	280	1,361	321
Provision for acquired credit impaired loans	0	0	0	0
Ending balance	1,660	1,121	1,660	1,121
Unallocated Financing Receivables [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	4	1,014	38	912
Provision (recovery of provision)	33	(87)	(1)	15
Provision for acquired credit impaired loans	0	0	0	0
Ending balance	$ 37	$ 927	$ 37	$ 927