Guarantees, Commitments and Contingencies (Narrative) (Details)	3 Months Ended		6 Months Ended	12 Months Ended
	Mar. 31, 2019 USD ($)	Jun. 30, 2018 USD ($) Apartment	Jun. 30, 2018 USD ($) Apartment	Dec. 31, 2018 USD ($)
Commitments, Contingencies and Guarantees [Line Items]
Number of apartments under the project | Apartment		37	37
Limited partner capital contribution commitment		$ 7,579,000	$ 7,579,000
Project investment amortization period		10 years	10 years
Annual LIHTCs mount awarded for the project		$ 861,000	$ 861,000
Total anticipated LIHTCs amount under the housing project		$ 8,613,000	$ 8,613,000
Total investment in limited partnership	$ 222,000			$ 233,000
Minimum net assets qualified for small banks assessment credits	10,000,000,000
Total assessment credit	$ 492,000
Minimum [Member]
Commitments, Contingencies and Guarantees [Line Items]
Small bank growth reserve ratio	1.15%
Reserve ratio for assessment credits to be contingent	1.38%
Maximum [Member]
Commitments, Contingencies and Guarantees [Line Items]
Small bank growth reserve ratio	1.35%
Other Assets [Member]
Commitments, Contingencies and Guarantees [Line Items]
Total investment in limited partnership	$ 2,744,000			1,710,000
Financial Standby Letters of Credit [Member]
Commitments, Contingencies and Guarantees [Line Items]
Commitments to extend credit	$ 19,758,000			$ 20,839,000