Loans Receivable and Allowance for Loan Losses (Narrative) (Details)	3 Months Ended		12 Months Ended
	Mar. 31, 2019 USD ($) property loan	Mar. 31, 2018 USD ($)	Dec. 31, 2018 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Impaired Financing Receivable, Average Recorded Investment	$ 885,000	$ 1,242,000
Impaired Financing Receivable, Interest Income, Cash Basis Method	0	14,000
Foreclosed Real Estate Expense	23,000	(19,000)
Acquired Loans with Specific Evidence of Deterioration in Credit Quality, Outstanding Balance	985,000		$ 1,055,000
Real Estate Acquired Through Foreclosure	1,792,000		1,115,000
Real Estate Acquired Through Deed-in-lieu, During Period	$ 680,000
Number Of Properties Acquired Through Foreclosure | property	1
Number Of Properties Acquired Through Deed-in-lieu | property	3
Loans and Leases Receivable, Gross	$ 864,314,000		$ 850,302,000
Charge Offs	$ 598,000	99,000
Historical loss factor	0.22%		0.42%
Mortgage loans originated for sale	$ 732,000	0
Proceeds from Sale of Foreclosed Assets	44,000	412,000
Multiple Properties [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Real Estate Acquired Through Foreclosure	$ 36,000
Number Of Properties Disposed By Sale | property	1
Commercial Rentals [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	$ 73,400,000
Commercial Rentals [Member] | Loans Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration Risk, Percentage	8.50%
Hospitality Lodging Industry [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross	$ 59,100,000
Hospitality Lodging Industry [Member] | Loans Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration Risk, Percentage	6.80%
Residential Real Estate Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Impaired Financing Receivable, Average Recorded Investment	$ 0	23,000
Impaired Financing Receivable, Interest Income, Cash Basis Method	$ 0	0
Number Of Properties Under Foreclosure Proceedings | property	2
Mortgage Loans in Process of Foreclosure, Amount	$ 221,000
Loans and Leases Receivable, Gross	231,954,000		$ 235,523,000
Charge Offs	65,000	51,000
Commercial Real Estate Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Impaired Financing Receivable, Average Recorded Investment	885,000	1,219,000
Impaired Financing Receivable, Interest Income, Cash Basis Method	0	14,000
Real Estate Acquired Through Foreclosure	32,000
Loans and Leases Receivable, Gross	373,276,000		374,790,000
Charge Offs	469,000	$ 0
Troubled Debt Restructured Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Impaired Financing Receivable, Related Allowance	$ 0		0
New Loans Identified as Troubled Debt Restructurings, Number of Loans | loan	0
Real Estate Acquired Through Foreclosure	$ 608,000
Financing Receivable, Modifications, Recorded Investment	107,000,000,000		$ 1,100,000
Proceeds from Sale of Foreclosed Assets	451,000
Delaware Bancshares, Inc. Acquisition [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired Loans with Specific Evidence of Deterioration in Credit Quality, Outstanding Balance	1,397,000
Assets, Fair Value Adjustment	499,000
Minimum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Annual Loan Review threshold, amount	$ 1,500,000