Loans, Nonaccrual Loans Segregated by Class of Loans and Loan Portfolio Aging Analysis, Segregated by Class (Details) - USD ($) $ in Thousands		6 Months Ended
		Jun. 30, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans segregated by class of loans		$ 19,651	$ 16,623
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		42,015	42,089
Current		3,045,327	2,896,282
Total Loans		3,087,342	2,938,371
90+ and Accruing	[1]	8,362	10,847
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		9,607	10,242
60-89 Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		9,436	7,324
90+ Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		$ 22,972	24,523
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		$ 1,608,359	1,508,097
Commercial [Member] | Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans segregated by class of loans		1,328	1,912
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		1,352	1,962
Current		70,702	65,036
Total Loans		72,054	66,998
90+ and Accruing	[1]	24	28
Commercial [Member] | Construction [Member] | 30-59 Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		0	22
Commercial [Member] | Construction [Member] | 60-89 Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		0	0
Commercial [Member] | Construction [Member] | 90+ Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		1,352	1,940
Commercial [Member] | Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans segregated by class of loans		8,713	6,326
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		13,569	11,358
Current		1,165,660	1,074,070
Total Loans		1,179,229	1,085,428
90+ and Accruing	[1]	2,171	3,015
Commercial [Member] | Real Estate [Member] | 30-59 Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		2,272	2,033
Commercial [Member] | Real Estate [Member] | 60-89 Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		3,540	478
Commercial [Member] | Real Estate [Member] | 90+ Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		7,757	8,847
Commercial [Member] | Equipment Lease Financing [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		130	0
Current		4,773	5,512
Total Loans		4,903	5,512
90+ and Accruing	[1]	130	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	0
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		130	0
Commercial [Member] | Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans segregated by class of loans		1,404	1,559
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		2,056	2,354
Current		350,117	347,805
Total Loans		352,173	350,159
90+ and Accruing	[1]	235	141
Commercial [Member] | Other [Member] | 30-59 Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		513	997
Commercial [Member] | Other [Member] | 60-89 Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		420	122
Commercial [Member] | Other [Member] | 90+ Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		1,123	1,235
Residential [Member] | Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans segregated by class of loans		189	11
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		1,824	901
Current		56,742	57,065
Total Loans		58,566	57,966
90+ and Accruing	[1]	205	152
Residential [Member] | Construction [Member] | 30-59 Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		1,254	707
Residential [Member] | Construction [Member] | 60-89 Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		177	42
Residential [Member] | Construction [Member] | 90+ Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		393	152
Residential [Member] | Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans segregated by class of loans		7,461	6,260
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		16,333	17,466
Current		692,134	685,503
Total Loans		708,467	702,969
90+ and Accruing	[1]	5,042	6,295
Residential [Member] | Real Estate [Member] | 30-59 Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		950	1,493
Residential [Member] | Real Estate [Member] | 60-89 Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		4,113	5,278
Residential [Member] | Real Estate [Member] | 90+ Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		11,270	10,695
Residential [Member] | Home Equity [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans segregated by class of loans		556	555
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		1,957	2,022
Current		91,764	89,489
Total Loans		93,721	91,511
90+ and Accruing	[1]	300	467
Residential [Member] | Home Equity [Member] | 30-59 Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		1,004	829
Residential [Member] | Home Equity [Member] | 60-89 Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		261	288
Residential [Member] | Home Equity [Member] | 90+ Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		692	905
Consumer [Member] | Consumer Direct [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		954	1,206
Current		134,274	131,887
Total Loans		135,228	133,093
90+ and Accruing	[1]	34	68
Consumer [Member] | Consumer Direct [Member] | 30-59 Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		788	873
Consumer [Member] | Consumer Direct [Member] | 60-89 Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		132	265
Consumer [Member] | Consumer Direct [Member] | 90+ Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		34	68
Consumer [Member] | Consumer Indirect [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		3,840	4,820
Current		479,161	439,915
Total Loans		483,001	444,735
90+ and Accruing	[1]	221	681
Consumer [Member] | Consumer Indirect [Member] | 30-59 Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		2,826	3,288
Consumer [Member] | Consumer Indirect [Member] | 60-89 Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		793	851
Consumer [Member] | Consumer Indirect [Member] | 90+ Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		$ 221	$ 681

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