Debt (Textuals) (Details) - USD ($)	3 Months Ended
	Sep. 30, 2020	Jun. 30, 2020
Long-term Debt Instruments [Line Items]
Letters of Credit Outstanding, Amount	$ 4,499,000	$ 4,475,000
Revolving Credit Facility [Member]
Long-term Debt Instruments [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	250,000,000
Letters of Credit Outstanding, Amount	731,000	1,873,000
Line of Credit Facility, Remaining Borrowing Capacity	$ 249,269,000	248,127,000
Revolving Credit Facility [Member] | Minimum [Member]
Long-term Debt Instruments [Line Items]
Line of Credit Facility, Commitment Fee Percentage	0.10%
Revolving Credit Facility [Member] | Maximum [Member]
Long-term Debt Instruments [Line Items]
Line of Credit Facility, Commitment Fee Percentage	0.20%
Long-term Debt [Member]
Long-term Debt Instruments [Line Items]
Debt Instrument, Face Amount	$ 780,000,000
Long-term Debt	$ 579,500,000	589,250,000
Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate	1.94%
Asset-backed Securities, Securitized Loans and Receivables [Member]
Long-term Debt Instruments [Line Items]
Debt Instrument, Face Amount	$ 175,000,000
Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate	1.07%
Debt Instrument, Fee	$ 0.0090
Prudential Facility [Domain]
Long-term Debt Instruments [Line Items]
Long-term Debt	$ 130,000,000	170,000,000
Prudential Facility [Domain] | Minimum [Member]
Long-term Debt Instruments [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	0.25%
Prudential Facility [Domain] | Maximum [Member]
Long-term Debt Instruments [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	1.25%
Prudential Facility - Series C [Member]
Long-term Debt Instruments [Line Items]
Debt Instrument, Face Amount	$ 120,000,000
Long-term Debt	$ 80,000,000	120,000,000
Long-term Debt, Percentage Bearing Fixed Interest, Percentage Rate	3.19%
Repayments of Debt	$ 40,000,000
Prudential Facility - Series D [Member]
Long-term Debt Instruments [Line Items]
Long-term Debt	$ 25,000,000	25,000,000
Long-term Debt, Percentage Bearing Fixed Interest, Percentage Rate	3.21%
Prudential Facility - Series E [Member] [Member]
Long-term Debt Instruments [Line Items]
Long-term Debt	$ 25,000,000	25,000,000
Long-term Debt, Percentage Bearing Fixed Interest, Percentage Rate	3.08%
State of Ohio Assumed Debt [Member]
Long-term Debt Instruments [Line Items]
Debt Instrument, Face Amount	$ 2,359,000
Long-term Debt	$ 1,026,000	$ 1,026,000
Long-term Debt, Percentage Bearing Fixed Interest, Percentage Rate	1.50%