Loans and Leases - Aging Analysis of Past Due Payments for Each Loan Portfolio Segment (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Aging analysis of past due payments for each loan portfolio segment [Abstract]
Current	$ 588,631,000		$ 588,631,000		$ 594,247,000
Total	594,565,000	$ 575,818,000	594,565,000	$ 575,818,000	602,009,000
Interest income lost on non-accrual loans	109,000	135,000	335,000	450,000
Financing Receivables, 30 to 59 Days Past Due
Aging analysis of past due payments for each loan portfolio segment [Abstract]
Total	635,000		635,000		1,742,000
Financing Receivables, 60 to 89 Days Past Due
Aging analysis of past due payments for each loan portfolio segment [Abstract]
Total	217,000		217,000		978,000
Financing Receivables, Equal to Greater than 90 Days Past Due
Aging analysis of past due payments for each loan portfolio segment [Abstract]
Total	5,082,000		5,082,000		5,042,000
Commercial real estate
Aging analysis of past due payments for each loan portfolio segment [Abstract]
Current	254,907,000		254,907,000		260,168,000
Total	256,452,000	253,074,000	256,452,000	253,074,000	261,561,000
Commercial real estate | Financing Receivables, 30 to 59 Days Past Due
Aging analysis of past due payments for each loan portfolio segment [Abstract]
Financing Receivable, Recorded Investment, Past Due	65,000		65,000		0
Commercial real estate | Financing Receivables, 60 to 89 Days Past Due
Aging analysis of past due payments for each loan portfolio segment [Abstract]
Financing Receivable, Recorded Investment, Past Due	0		0		507,000
Commercial real estate | Financing Receivables, Equal to Greater than 90 Days Past Due
Aging analysis of past due payments for each loan portfolio segment [Abstract]
Financing Receivable, Recorded Investment, Past Due	1,480,000		1,480,000		886,000
Construction and land development
Aging analysis of past due payments for each loan portfolio segment [Abstract]
Current	78,261,000		78,261,000		83,225,000
Total	78,389,000	74,885,000	78,389,000	74,885,000	83,369,000
Construction and land development | Financing Receivables, 30 to 59 Days Past Due
Aging analysis of past due payments for each loan portfolio segment [Abstract]
Financing Receivable, Recorded Investment, Past Due	0		0		0
Construction and land development | Financing Receivables, 60 to 89 Days Past Due
Aging analysis of past due payments for each loan portfolio segment [Abstract]
Financing Receivable, Recorded Investment, Past Due	0		0		0
Construction and land development | Financing Receivables, Equal to Greater than 90 Days Past Due
Aging analysis of past due payments for each loan portfolio segment [Abstract]
Financing Receivable, Recorded Investment, Past Due	128,000		128,000		144,000
Commercial and industrial
Aging analysis of past due payments for each loan portfolio segment [Abstract]
Current	110,211,000		110,211,000		107,190,000
Total	110,861,000	106,254,000	110,861,000	106,254,000	108,146,000
Commercial and industrial | Financing Receivables, 30 to 59 Days Past Due
Aging analysis of past due payments for each loan portfolio segment [Abstract]
Financing Receivable, Recorded Investment, Past Due	0		0		416,000
Commercial and industrial | Financing Receivables, 60 to 89 Days Past Due
Aging analysis of past due payments for each loan portfolio segment [Abstract]
Financing Receivable, Recorded Investment, Past Due	0		0		367,000
Commercial and industrial | Financing Receivables, Equal to Greater than 90 Days Past Due
Aging analysis of past due payments for each loan portfolio segment [Abstract]
Financing Receivable, Recorded Investment, Past Due	650,000		650,000		173,000
Multi-family
Aging analysis of past due payments for each loan portfolio segment [Abstract]
Current	33,751,000		33,751,000		23,389,000
Total	33,751,000	23,831,000	33,751,000	23,831,000	23,389,000
Multi-family | Financing Receivables, 30 to 59 Days Past Due
Aging analysis of past due payments for each loan portfolio segment [Abstract]
Financing Receivable, Recorded Investment, Past Due	0		0		0
Multi-family | Financing Receivables, 60 to 89 Days Past Due
Aging analysis of past due payments for each loan portfolio segment [Abstract]
Financing Receivable, Recorded Investment, Past Due	0		0		0
Multi-family | Financing Receivables, Equal to Greater than 90 Days Past Due
Aging analysis of past due payments for each loan portfolio segment [Abstract]
Financing Receivable, Recorded Investment, Past Due	0		0		0
Residential real estate
Aging analysis of past due payments for each loan portfolio segment [Abstract]
Current	55,033,000		55,033,000		55,566,000
Total	55,643,000	49,061,000	55,643,000	49,061,000	56,899,000
Residential real estate | Financing Receivables, 30 to 59 Days Past Due
Aging analysis of past due payments for each loan portfolio segment [Abstract]
Financing Receivable, Recorded Investment, Past Due	99,000		99,000		978,000
Residential real estate | Financing Receivables, 60 to 89 Days Past Due
Aging analysis of past due payments for each loan portfolio segment [Abstract]
Financing Receivable, Recorded Investment, Past Due	0		0		0
Residential real estate | Financing Receivables, Equal to Greater than 90 Days Past Due
Aging analysis of past due payments for each loan portfolio segment [Abstract]
Financing Receivable, Recorded Investment, Past Due	511,000		511,000		355,000
Leases
Aging analysis of past due payments for each loan portfolio segment [Abstract]
Current	52,954,000		52,954,000		59,809,000
Total	55,270,000	62,671,000	55,270,000	62,671,000	61,838,000
Leases | Financing Receivables, 30 to 59 Days Past Due
Aging analysis of past due payments for each loan portfolio segment [Abstract]
Financing Receivable, Recorded Investment, Past Due	255,000		255,000		348,000
Leases | Financing Receivables, 60 to 89 Days Past Due
Aging analysis of past due payments for each loan portfolio segment [Abstract]
Financing Receivable, Recorded Investment, Past Due	217,000		217,000		104,000
Leases | Financing Receivables, Equal to Greater than 90 Days Past Due
Aging analysis of past due payments for each loan portfolio segment [Abstract]
Financing Receivable, Recorded Investment, Past Due	1,844,000		1,844,000		1,577,000
Tax certificates
Aging analysis of past due payments for each loan portfolio segment [Abstract]
Current	821,000		821,000		1,798,000
Total	1,290,000	3,803,000	1,290,000	3,803,000	3,705,000
Tax certificates | Financing Receivables, 30 to 59 Days Past Due
Aging analysis of past due payments for each loan portfolio segment [Abstract]
Financing Receivable, Recorded Investment, Past Due	0		0		0
Tax certificates | Financing Receivables, 60 to 89 Days Past Due
Aging analysis of past due payments for each loan portfolio segment [Abstract]
Financing Receivable, Recorded Investment, Past Due	0		0		0
Tax certificates | Financing Receivables, Equal to Greater than 90 Days Past Due
Aging analysis of past due payments for each loan portfolio segment [Abstract]
Financing Receivable, Recorded Investment, Past Due	469,000		469,000		1,907,000
Consumer
Aging analysis of past due payments for each loan portfolio segment [Abstract]
Current	2,693,000		2,693,000		3,102,000
Total	2,909,000	$ 2,239,000	2,909,000	$ 2,239,000	3,102,000
Consumer | Financing Receivables, 30 to 59 Days Past Due
Aging analysis of past due payments for each loan portfolio segment [Abstract]
Financing Receivable, Recorded Investment, Past Due	216,000		216,000		0
Consumer | Financing Receivables, 60 to 89 Days Past Due
Aging analysis of past due payments for each loan portfolio segment [Abstract]
Financing Receivable, Recorded Investment, Past Due	0		0		0
Consumer | Financing Receivables, Equal to Greater than 90 Days Past Due
Aging analysis of past due payments for each loan portfolio segment [Abstract]
Financing Receivable, Recorded Investment, Past Due	$ 0		$ 0		$ 0