Loans and Leases - Reserve for Loan and Lease Losses Roll Forward (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	$ 31,602	$ 23,410	$ 29,364	$ 21,555
Charge-offs	(1,216)	(13,296)	(1,925)	(14,165)
Recoveries	138	129	400	800
Provision (recovery of provision)	2,076	15,409	4,760	17,461
Provision for acquired credit impaired loans			1	1
Ending balance	32,600	25,652	32,600	25,652
Commercial, Financial and Agricultural [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	8,950	6,942	7,983	6,742
Charge-offs	(1,018)	(13,048)	(1,486)	(13,649)
Recoveries	19	23	101	249
Provision (recovery of provision)	1,178	13,341	2,531	13,916
Provision for acquired credit impaired loans			0	0
Ending balance	9,129	7,258	9,129	7,258
Real Estate-Commercial and Construction [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	14,981	11,178	13,903	9,839
Charge-offs	(33)	0	(74)	(40)
Recoveries	0	0	91	73
Provision (recovery of provision)	530	1,149	1,558	2,455
Provision for acquired credit impaired loans			0	0
Ending balance	15,478	12,327	15,478	12,327
Real Estate-Residential Secured for Business Purpose [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	2,302	1,871	2,236	1,661
Charge-offs	0	0	0	0
Recoveries	6	7	10	258
Provision (recovery of provision)	170	126	232	85
Provision for acquired credit impaired loans			0	0
Ending balance	2,478	2,004	2,478	2,004
Real Estate-Residential and Home Equity Secured for Personal Purpose [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	3,379	1,908	3,199	1,754
Charge-offs	(4)	0	(15)	0
Recoveries	7	8	12	65
Provision (recovery of provision)	136	578	321	674
Provision for acquired credit impaired loans			1	1
Ending balance	3,518	2,494	3,518	2,494
Loans to Individuals [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	469	372	484	373
Charge-offs	(51)	(79)	(136)	(171)
Recoveries	16	16	38	46
Provision (recovery of provision)	47	138	95	199
Provision for acquired credit impaired loans			0	0
Ending balance	481	447	481	447
Lease Financings [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	1,275	1,079	1,288	1,132
Charge-offs	(110)	(169)	(214)	(305)
Recoveries	90	75	148	109
Provision (recovery of provision)	(14)	86	19	135
Provision for acquired credit impaired loans			0	0
Ending balance	1,241	1,071	1,241	1,071
Unallocated Financing Receivables [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	246	60	271	54
Provision (recovery of provision)	29	(9)	4	(3)
Provision for acquired credit impaired loans			0	0
Ending balance	$ 275	$ 51	$ 275	$ 51