Loans, Nonaccrual Loans Segregated by Class of Loans and Loan Portfolio Aging Analysis, Segregated by Class (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans segregated by class of loans		$ 16,623	$ 16,563
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		42,089	40,279
Current		2,896,282	2,833,682
Total Loans		2,938,371	2,873,961
90+ and Accruing	[1]	10,847	12,046
Minimum threshold amount of loans requiring performance bond		500
30-59 Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		10,242	9,010
60-89 Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		7,324	6,140
90+ Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		$ 24,523	25,129
Equipment Lease Financing [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Financing percentage requested for underwriting loans		100.00%
Commercial [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Loans		$ 1,508,097	1,498,351
Commercial [Member] | Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans segregated by class of loans		1,912	3,402
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		1,962	3,473
Current		65,036	74,547
Total Loans		66,998	78,020
90+ and Accruing	[1]	28	30
Commercial [Member] | Construction [Member] | 30-59 Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		22	36
Commercial [Member] | Construction [Member] | 60-89 Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		0	6
Commercial [Member] | Construction [Member] | 90+ Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		1,940	3,431
Commercial [Member] | Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans segregated by class of loans		6,326	5,928
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		11,358	11,492
Current		1,074,070	1,041,427
Total Loans		1,085,428	1,052,919
90+ and Accruing	[1]	3,015	3,757
Commercial [Member] | Real Estate [Member] | 30-59 Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		2,033	2,947
Commercial [Member] | Real Estate [Member] | 60-89 Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		478	622
Commercial [Member] | Real Estate [Member] | 90+ Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		8,847	7,923
Commercial [Member] | Equipment Lease Financing [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		0	199
Current		5,512	8,315
Total Loans		5,512	8,514
90+ and Accruing	[1]	0	0
Commercial [Member] | Equipment Lease Financing [Member] | 30-59 Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		0	199
Commercial [Member] | Equipment Lease Financing [Member] | 60-89 Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		0	0
Commercial [Member] | Equipment Lease Financing [Member] | 90+ Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		0	0
Commercial [Member] | Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans segregated by class of loans		1,559	1,485
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		2,354	2,359
Current		347,805	356,539
Total Loans		350,159	358,898
90+ and Accruing	[1]	141	310
Commercial [Member] | Other [Member] | 30-59 Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		997	762
Commercial [Member] | Other [Member] | 60-89 Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		122	121
Commercial [Member] | Other [Member] | 90+ Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		1,235	1,476
Residential [Member] | Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans segregated by class of loans		11	249
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		901	796
Current		57,065	60,954
Total Loans		57,966	61,750
90+ and Accruing	[1]	152	55
Residential [Member] | Construction [Member] | 30-59 Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		707	443
Residential [Member] | Construction [Member] | 60-89 Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		42	62
Residential [Member] | Construction [Member] | 90+ Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		152	291
Residential [Member] | Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans segregated by class of loans		6,260	5,206
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		17,466	15,923
Current		685,503	691,951
Total Loans		702,969	707,874
90+ and Accruing	[1]	6,295	6,925
Residential [Member] | Real Estate [Member] | 30-59 Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		1,493	1,128
Residential [Member] | Real Estate [Member] | 60-89 Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		5,278	3,888
Residential [Member] | Real Estate [Member] | 90+ Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		10,695	10,907
Residential [Member] | Home Equity [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans segregated by class of loans		555	183
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		2,022	1,255
Current		89,489	88,195
Total Loans		91,511	89,450
90+ and Accruing	[1]	467	448
Residential [Member] | Home Equity [Member] | 30-59 Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		829	527
Residential [Member] | Home Equity [Member] | 60-89 Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		288	148
Residential [Member] | Home Equity [Member] | 90+ Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		905	580
Consumer [Member] | Consumer Direct [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans segregated by class of loans		0	110
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		1,206	1,440
Current		131,887	124,966
Total Loans		133,093	126,406
90+ and Accruing	[1]	68	126
Consumer [Member] | Consumer Direct [Member] | 30-59 Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		873	835
Consumer [Member] | Consumer Direct [Member] | 60-89 Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		265	479
Consumer [Member] | Consumer Direct [Member] | 90+ Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		68	126
Consumer [Member] | Consumer Indirect [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		4,820	3,342
Current		439,915	386,788
Total Loans		444,735	390,130
90+ and Accruing	[1]	681	395
Consumer [Member] | Consumer Indirect [Member] | 30-59 Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		3,288	2,133
Consumer [Member] | Consumer Indirect [Member] | 60-89 Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		851	814
Consumer [Member] | Consumer Indirect [Member] | 90+ Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		$ 681	$ 395

[1] 90+ and Accruing are also included in 90+ Days Past Due column.