Summary of Significant Accounting Policies (Narrative) (Details)		12 Months Ended
	Jan. 01, 2018 USD ($)	Dec. 31, 2018 USD ($) segment loan item	Dec. 31, 2017 USD ($) loan
Summary Of Significant Accounting Policies [Line Items]
Non-cash funding of retirement plans		$ 584,000	$ 542,000
Number of community offices, providing investment and trust services | item		15
Number of operating segments | segment		1
Collection of the original recorded investment on HTM securities (percentage)		85.00%
Impairment charges on securities		$ 0	0
Restricted stock		$ 5,616,000	7,641,000
Accrual of interest general discontinued period, in days		90 days
General charge-off period, in days		120 days
Partial charge-off of loan amount		$ 742,000	$ 1,325,000
Number of TDR loans | loan		9	8
TDR recorded investment		$ 1,762,000	$ 1,857,000
Loan defaults on TDRs		0	0
Reserve for unfunded loan commitments		395,000	348,000
Unrecognized tax positions		$ 0
Age of eligibility for noncontributory defined benefit pension plan		21 years
Defined benefit pension plan requisite service period, in years		1 year
Highest consecutive years of average-compensation (years)		5 years
Defined benefit pension plan, years of service		10 years
Advertising and marketing		$ 711,000	755,000
Federal Home Loan Bank Of Pittsburgh [Member]
Summary Of Significant Accounting Policies [Line Items]
Restricted stock		3,100,000	5,200,000
Federal Reserve Bank Of Philadelphia [Member]
Summary Of Significant Accounting Policies [Line Items]
Restricted stock		2,300,000	2,300,000
Atlantic Central Bankers Bank [Member]
Summary Of Significant Accounting Policies [Line Items]
Restricted stock		$ 156,000	$ 156,000
Accounting Standards Update 2018-02 [Member]
Summary Of Significant Accounting Policies [Line Items]
Reclassification amount from accumulated other comprehensive income related to Tax Cuts and jobs Act	$ 471,000
Commercial Mortgage [Member]
Summary Of Significant Accounting Policies [Line Items]
Number of TDR loans | loan		1	3
TDR recorded investment		$ 73,000	$ 992,000
Real estate loans in process of foreclosure		58,000	416,000
Consumer Installment Loan [Member]
Summary Of Significant Accounting Policies [Line Items]
Partial charge-off of loan amount		$ 2,000	$ 2,000
Number of TDR loans | loan		1	1
Consumer: Home Equity [Member]
Summary Of Significant Accounting Policies [Line Items]
Number of TDR loans | loan			5
TDR recorded investment			$ 1,128,000
Nonaccrual Impaired Loans [Member]
Summary Of Significant Accounting Policies [Line Items]
Number of TDR loans | loan			3
TDR recorded investment			$ 729,000
Residential Mortgage [Member]
Summary Of Significant Accounting Policies [Line Items]
Partial charge-off of loan amount		$ 151,000	$ 151,000
Number of TDR loans | loan		2	2