Loans and Leases - Reserve for Loan and Lease Losses Roll Forward (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	$ 20,910	$ 17,153	$ 17,499	$ 17,628
Charge-offs	(3,587)	(2,189)	(6,002)	(5,091)
Recoveries	531	520	1,146	1,791
Provision (recovery of provision)	2,690	1,416	7,899	2,396
Provision for acquired credit impaired loans	(1)	(1)	1	175
Ending balance	20,543	16,899	20,543	16,899
Commercial, Financial and Agricultural [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	8,313	5,788	7,037	6,418
Charge-offs	(290)	(1,753)	(576)	(3,580)
Recoveries	325	351	722	1,316
Provision (recovery of provision)	(1,732)	1,300	(567)	1,532
Provision for acquired credit impaired loans	0	0	0	0
Ending balance	6,616	5,686	6,616	5,686
Real Estate-Commercial and Construction [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	8,468	7,549	7,505	6,572
Charge-offs	0	(100)	(30)	(305)
Recoveries	1	83	4	99
Provision (recovery of provision)	787	(388)	1,777	600
Provision for acquired credit impaired loans	0	0	0	178
Ending balance	9,256	7,144	9,256	7,144
Real Estate-Residential Secured for Business Purpose [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	1,129	56	774	763
Charge-offs	(56)	(3)	(1,237)	(268)
Recoveries	29	9	47	62
Provision (recovery of provision)	204	(32)	1,722	(527)
Provision for acquired credit impaired loans	(1)	0	(1)	0
Ending balance	1,305	30	1,305	30
Real Estate-Residential and Home Equity Secured for Personal Purpose [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	974	1,301	993	1,575
Charge-offs	(83)	(34)	(177)	(90)
Recoveries	68	15	89	66
Provision (recovery of provision)	756	268	808	1
Provision for acquired credit impaired loans	0	(1)	2	(3)
Ending balance	1,715	1,549	1,715	1,549
Loans to Individuals [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	329	411	364	346
Charge-offs	(61)	(123)	(301)	(307)
Recoveries	35	28	116	91
Provision (recovery of provision)	51	114	175	300
Provision for acquired credit impaired loans	0	0	0	0
Ending balance	354	430	354	430
Lease Financings [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	1,660	1,121	788	1,042
Charge-offs	(3,097)	(176)	(3,681)	(541)
Recoveries	73	34	168	157
Provision (recovery of provision)	2,654	184	4,015	505
Provision for acquired credit impaired loans	0	0	0	0
Ending balance	1,290	1,163	1,290	1,163
Unallocated Financing Receivables [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	37	927	38	912
Provision (recovery of provision)	(30)	(30)	(31)	(15)
Provision for acquired credit impaired loans	0	0	0	0
Ending balance	$ 7	$ 897	$ 7	$ 897