Fair Values of Financial Instruments - Estimated Fair Value and Related Carrying Values of Financial Instruments (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Carrying Amount
Financial assets:
Cash and due from banks	$ 16,375	$ 24,347
Interest bearing deposits	20,809	4,093
Federal funds sold	7,395	1,254
Securities: Available for sale	50,917	51,300
Loans, net of allowance for credit losses	639,649	625,513
Accrued interest receivable	2,235	2,103
Federal Home Loan Bank stock	2,761	2,652
Atlantic Central Bankers stock	131	131
Other investments	1,559	1,537
Financial liabilities:
Deposits	639,516	614,925
Accrued interest payable	516	392
FHLB advances and notes payable	55,660	56,989
Unrecognized financial instruments:
Commitments to extend credit	104,565	114,395
Standby letters of credit	2,644	3,276
Estimated Fair Value
Financial assets:
Cash and due from banks	16,375	24,347
Interest bearing deposits	20,809	4,093
Federal funds sold	7,395	1,254
Securities: Available for sale	50,917	51,300
Loans, net of allowance for credit losses	619,552	604,290
Accrued interest receivable	2,235	2,103
Federal Home Loan Bank stock	2,761	2,652
Atlantic Central Bankers stock	131	131
Other investments	1,559	1,537
Financial liabilities:
Deposits	606,769	570,509
Accrued interest payable	516	392
FHLB advances and notes payable	56,267	56,979
Unrecognized financial instruments:
Commitments to extend credit	104,565	114,395
Standby letters of credit	$ 2,644	$ 3,276