Commitments and Contingent Liabilities and Guarantees (Narrative) (Details) - USD ($)	9 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Loss Contingencies [Line Items]
Letter of Credit expiration period	1 year
Commitments to Grant Loans [Member]
Loss Contingencies [Line Items]
Outstanding loans commitments and other unused lines of credit	$ 72,851,000	$ 77,023,000
Outstanding Letters of Credit [Member]
Loss Contingencies [Line Items]
Outstanding loans commitments and other unused lines of credit	3,027,000	2,541,000
Commercial Letter Of Credit [Member]
Loss Contingencies [Line Items]
Outstanding loans commitments and other unused lines of credit	$ 11,983,000	$ 12,650,000