Fair Value Measurements Fair Value, Assets Measured on Nonrecurring Basis, Valuation Techniques (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Sep. 30, 2017	Mar. 31, 2017
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Other Real Estate, Foreclosed Assets, and Repossessed Assets	$ 604	$ 787
Fair Value, Measurements, Nonrecurring
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Impaired Financing Receivable, with Related Allowance, Recorded Investment	3,417	5,953
Other Real Estate, Foreclosed Assets, and Repossessed Assets	604	990
Fair Value, Measurements, Nonrecurring | Fair Value, Inputs, Level 3
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Impaired Financing Receivable, with Related Allowance, Recorded Investment	3,417	5,953
Other Real Estate, Foreclosed Assets, and Repossessed Assets	$ 604	$ 990
Fair Value Measurements, Valuation Techniques	Appraisal of collateral	Appraisal of collateral
Fair Value Measurements, Significant Assumptions	Appraisal adjustments	Appraisal adjustments