Fair Value Measurements Fair Value, Assets Measured on Recurring Basis, Valuation Techniques (Details) $ in Thousands	3 Months Ended		12 Months Ended
	Jun. 30, 2018 USD ($)		Mar. 31, 2018 USD ($)	Mar. 31, 2017 USD ($)	Jun. 30, 2017 USD ($)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage servicing rights			$ 181
Equity securities	$ 9,710		0
Fair Value, Inputs, Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage servicing rights	174		181
Fair Value, Measurements, Recurring
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage servicing rights	174		181
Equity securities	9,710
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgage servicing rights			181
Equity securities	431
Fair Value, Measurements, Recurring | Other investments | Fair Value, Inputs, Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value			$ 433	$ 403	$ 403
Fair Value Measurements, Valuation Processes, Description			Cost
Fair Value, Measurements, Recurring | Equity Investments | Fair Value, Inputs, Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	$ 431		$ 433
Fair Value Measurements, Valuation Processes, Description	Cost
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings, Description	n/a			n/a
Fair Value, Measurements, Recurring | Other Assets | Fair Value, Inputs, Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	$ 174		$ 181	$ 192	$ 182
Fair Value Measurements, Valuation Processes, Description	Discounted Cash Flow		Discounted Cash Flow
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings, Description	Weighted Average Constant Prepayment Rate(1)	[1]	Weighted Average Constant Prepayment Rate(1)
Mortgage servicing rights	$ 174
Servicing Asset, Measurement Input	0.1884		0.2003

[1] (1) Represents annualized loan repayment rate assumptions