Commercial Loans Receivables and Allowance for Loan Loss (Concentrations of Commercial Loans Receivables) (Details)	Jun. 30, 2018	Mar. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial Loans Receivable Principal Balance Concentration	22.30%	37.40%
ARIZONA
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial Loans Receivables Geographic Concentration Percentage	16.00%	16.70%
TEXAS
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial Loans Receivables Geographic Concentration Percentage	10.60%	9.00%
CALIFORNIA
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial Loans Receivables Geographic Concentration Percentage	13.40%	14.40%
OREGON
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial Loans Receivables Geographic Concentration Percentage	11.10%	14.70%