Investment Securities Investment Securities Text Tags (Details)	9 Months Ended
	Dec. 31, 2018 USD ($)	Mar. 31, 2018 USD ($)
Schedule of Investments [Line Items]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions	37	35
Available-for-sale	$ 102,330,000	$ 60,709,000
Percentage Available-for-sale Securities	89.70%
Held-to-maturity	$ 11,340,000	12,075,000
Percentage Held-to-maturity Securities	9.90%
Equity securities	$ 416,000	0
Percentage Equity Securities	0.40%
Trading	$ 0
Cumulative Effect of New Accounting Principle	0
Proceeds from Sale of Available-for-sale Securities	$ 0
Mortgage-backed securities
Schedule of Investments [Line Items]
Percentage Available-for-Sale, Continuos Unrealized Loss Position	32.70%
Number of AFS securities in Unrealized Loss Positions, greater than or equal to 12 months	18
Held-to-maturity	$ 10,340,000	11,075,000
US Government Agency Securities
Schedule of Investments [Line Items]
Percentage Available-for-Sale, Continuos Unrealized Loss Position	41.70%
Number of AFS securities in Unrealized Loss Positions, greater than or equal to 12 months	3
Corporate Bonds
Schedule of Investments [Line Items]
Number of AFS securities in Unrealized Loss Positions, greater than or equal to 12 months	5
Held-to-maturity	$ 1,000,000	$ 1,000,000
Accumulated Other Comprehensive Loss
Schedule of Investments [Line Items]
Cumulative Effect of New Accounting Principle	$ 721,000