Loans, Nonaccrual Loans Segregated by Class of Loans and Loan Portfolio Aging Analysis, Segregated by Class (Details) - USD ($)		6 Months Ended
		Jun. 30, 2016	Dec. 31, 2015
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans segregated by class of loans		$ 16,447,000	$ 16,563,000
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		41,863,000	40,279,000
Current		2,889,522,000	2,833,682,000
Total Loans		2,931,385,000	2,873,961,000
90+ and Accruing	[1]	8,237,000	12,046,000
Minimum threshold amount of loans requiring performance bond		500,000
30-59 Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		11,273,000	9,010,000
60-89 Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		10,977,000	6,140,000
90+ Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		$ 19,613,000	25,129,000
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		$ 1,522,668,000	1,498,351,000
Commercial [Member] | Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans segregated by class of loans		2,902,000	3,402,000
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		2,913,000	3,473,000
Current		66,100,000	74,547,000
Total Loans		69,013,000	78,020,000
90+ and Accruing	[1]	30,000	30,000
Commercial [Member] | Construction [Member] | 30-59 Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		19,000	36,000
Commercial [Member] | Construction [Member] | 60-89 Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		146,000	6,000
Commercial [Member] | Construction [Member] | 90+ Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		2,748,000	3,431,000
Commercial [Member] | Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans segregated by class of loans		5,391,000	5,928,000
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		13,212,000	11,492,000
Current		1,066,117,000	1,041,427,000
Total Loans		1,079,329,000	1,052,919,000
90+ and Accruing	[1]	2,258,000	3,757,000
Commercial [Member] | Real Estate [Member] | 30-59 Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		3,712,000	2,947,000
Commercial [Member] | Real Estate [Member] | 60-89 Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		4,465,000	622,000
Commercial [Member] | Real Estate [Member] | 90+ Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		5,035,000	7,923,000
Commercial [Member] | Equipment Lease Financing [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		0	199,000
Current		7,353,000	8,315,000
Total Loans		7,353,000	8,514,000
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	199,000
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		1,708,000	1,485,000
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		2,190,000	2,359,000
Current		364,783,000	356,539,000
Total Loans		366,973,000	358,898,000
90+ and Accruing	[1]	27,000	310,000
Commercial [Member] | Other [Member] | 30-59 Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		441,000	762,000
Commercial [Member] | Other [Member] | 60-89 Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		516,000	121,000
Commercial [Member] | Other [Member] | 90+ Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		1,233,000	1,476,000
Residential [Member] | Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans segregated by class of loans		123,000	249,000
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		1,962,000	796,000
Current		57,011,000	60,954,000
Total Loans		58,973,000	61,750,000
90+ and Accruing	[1]	741,000	55,000
Residential [Member] | Construction [Member] | 30-59 Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		816,000	443,000
Residential [Member] | Construction [Member] | 60-89 Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		294,000	62,000
Residential [Member] | Construction [Member] | 90+ Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		852,000	291,000
Residential [Member] | Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans segregated by class of loans		6,070,000	5,206,000
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		14,999,000	15,923,000
Current		693,461,000	691,951,000
Total Loans		708,460,000	707,874,000
90+ and Accruing	[1]	4,643,000	6,925,000
Residential [Member] | Real Estate [Member] | 30-59 Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		1,505,000	1,128,000
Residential [Member] | Real Estate [Member] | 60-89 Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		4,470,000	3,888,000
Residential [Member] | Real Estate [Member] | 90+ Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		9,024,000	10,907,000
Residential [Member] | Home Equity [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans segregated by class of loans		253,000	183,000
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		1,609,000	1,255,000
Current		87,576,000	88,195,000
Total Loans		89,185,000	89,450,000
90+ and Accruing	[1]	273,000	448,000
Residential [Member] | Home Equity [Member] | 30-59 Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		873,000	527,000
Residential [Member] | Home Equity [Member] | 60-89 Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		280,000	148,000
Residential [Member] | Home Equity [Member] | 90+ Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		456,000	580,000
Consumer [Member] | Consumer Direct [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual loans segregated by class of loans		0	110,000
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		1,080,000	1,440,000
Current		128,211,000	124,966,000
Total Loans		129,291,000	126,406,000
90+ and Accruing	[1]	68,000	126,000
Consumer [Member] | Consumer Direct [Member] | 30-59 Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		891,000	835,000
Consumer [Member] | Consumer Direct [Member] | 60-89 Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		121,000	479,000
Consumer [Member] | Consumer Direct [Member] | 90+ Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		68,000	126,000
Consumer [Member] | Consumer Indirect [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		3,898,000	3,342,000
Current		418,910,000	386,788,000
Total Loans		422,808,000	390,130,000
90+ and Accruing	[1]	197,000	395,000
Consumer [Member] | Consumer Indirect [Member] | 30-59 Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		3,016,000	2,133,000
Consumer [Member] | Consumer Indirect [Member] | 60-89 Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		685,000	814,000
Consumer [Member] | Consumer Indirect [Member] | 90+ Days Past Due [Member]
Bank's Loan portfolio aging analysis, segregated by class [Abstract]
Total Past Due		$ 197,000	$ 395,000

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