Loans and Leases - Reserve for Loan and Lease Losses Roll Forward (Details) $ in Thousands	3 Months Ended				9 Months Ended
	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($) loan borrowers	Mar. 31, 2015 USD ($)	Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	$ 19,602		$ 20,662	$ 24,094	$ 20,662	$ 24,494
Charge-offs	(2,471)			(2,857)	(6,334)	(6,838)
Recoveries	819			292	1,407	1,147
Provision (recovery of provision)	648			233	2,863	2,959
Provision for acquired credit impaired loans	22				22
Ending balance	18,620	$ 19,602		21,762	18,620	21,762
Commercial, Financial and Agricultural [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	6,847		6,920	9,714	6,920	9,789
Charge-offs	(1,917)			(968)	(3,255)	(2,657)
Recoveries	682			88	907	197
Provision (recovery of provision)	1,382			(1,219)	2,422	286
Provision for acquired credit impaired loans	0				0
Ending balance	6,994	6,847		7,615	6,994	7,615
Real Estate-Commercial and Construction [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Amount of Loans Charged Off Prior to Being Transferred to Loans Held For Sale		$ 1,300			1,300
Number of Loans Charged Off Prior to Being Transferred to Loans Held for Sale | loan		2
Number of Borrowers, Loans Charged Off Prior to Being Transferred to Loans Held for Sale | borrowers		1
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	7,801		8,943	9,263	8,943	8,780
Charge-offs	(138)			(1,570)	(1,834)	(2,878)
Recoveries	34			58	190	428
Provision (recovery of provision)	(795)			1,337	(397)	2,758
Provision for acquired credit impaired loans	9				9
Ending balance	6,911	$ 7,801		9,088	6,911	9,088
Real Estate-Residential Secured for Business Purpose [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	616		763	1,025	763	1,062
Charge-offs	(90)			(26)	(114)	(140)
Recoveries	8			9	21	57
Provision (recovery of provision)	(41)			(48)	(177)	(19)
Provision for acquired credit impaired loans	13				13
Ending balance	506	616		960	506	960
Real Estate-Residential and Home Equity Secured for Personal Purpose [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	1,188		1,124	1,248	1,124	1,284
Charge-offs	(10)			(18)	(148)	(108)
Recoveries	8			2	9	29
Provision (recovery of provision)	(3)			(54)	198	(27)
Provision for acquired credit impaired loans	0				0
Ending balance	1,183	1,188		1,178	1,183	1,178
Loans to Individuals [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	389		360	405	360	694
Charge-offs	(144)			(169)	(392)	(659)
Recoveries	40			53	129	212
Provision (recovery of provision)	130			43	318	85
Provision for acquired credit impaired loans	0				0
Ending balance	415	389		332	415	332
Lease Financings [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	1,125		985	1,101	985	1,285
Charge-offs	(172)			(106)	(591)	(396)
Recoveries	47			82	151	224
Provision (recovery of provision)	(1)			38	454	2
Provision for acquired credit impaired loans	0				0
Ending balance	999	1,125		1,115	999	1,115
Unallocated Financing Receivables [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	1,636		1,567	1,338	1,567	1,600
Provision (recovery of provision)	(24)			136	45	(126)
Provision for acquired credit impaired loans	0				0
Ending balance	1,612	$ 1,636		$ 1,474	$ 1,612	$ 1,474
Nonaccrual Troubled Debt Restructuring Loans [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Financing Receivables, Impaired, Troubled Debt Restructuring, Write-down	$ 98		$ 200