Debt Arrangements - Summary (Details) - USD ($)	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Oct. 14, 2016
Debt Instrument [Line Items]
Outstanding borrowings	$ 1,489,521,000	$ 1,327,679,000
Outstanding, credit facility	207,727,000
Short-term	540,157,000	428,961,000
Current portion of long-term debt	45,048,000	332,000
Long-term debt	904,316,000	898,386,000
Long-term debt, total	949,364,000	898,718,000
Remaining borrowing capacity of credit facility	213,499,000
Long-term Debt, by Maturity [Abstract]
2020	45,048,000
2021	903,756,000
2022	148,000
2023	148,000
2024	79,000
Later	185,000
Subordinated Debt | Senior Secured $275 Million 8.50% Note
Debt Instrument [Line Items]
Outstanding borrowings	272,871,000	270,883,000
Outstanding, credit facility	$ 0
Interest rate, notes (as a percent)	8.50%
Long-term Debt, by Maturity [Abstract]
2020	$ 0
2021	272,871,000
2022	0
2023	0
2024	0
Later	0
Unamortized discount of debt instrument	673,000
Unamortized debt issuance expense	1,456,000
Total repayments of debt	275,000,000
Subordinated Debt | 9.875% Senior Secured Second Lien Notes due 2021
Debt Instrument [Line Items]
Outstanding borrowings	630,737,000	627,147,000
Outstanding, credit facility	$ 0
Interest rate, notes (as a percent)	9.875%
Long-term Debt, by Maturity [Abstract]
2020	$ 0
2021	630,737,000
2022	0
2023	0
2024	0
Later	0
Unamortized discount of debt instrument	2,823,000
Unamortized debt issuance expense	2,126,000
Total repayments of debt	635,686,000
Other Long-term Debt
Debt Instrument [Line Items]
Outstanding borrowings	856,000	688,000
Outstanding, credit facility	$ 66,000
Interest rate (as a percent)	5.20%
Long-term Debt, by Maturity [Abstract]
2020	$ 148,000
2021	148,000
2022	148,000
2023	148,000
2024	79,000
Later	185,000
Notes Payable to Banks
Debt Instrument [Line Items]
Outstanding borrowings	540,157,000	428,961,000
Outstanding, credit facility	$ 192,561,000
Interest rate (as a percent)	6.90%
Long-term Debt, by Maturity [Abstract]
2020	$ 0
2021	0
2022	0
2023	0
2024	0
Later	0
Letter of Credit
Debt Instrument [Line Items]
Outstanding borrowings	7,027,000	5,399,000
Outstanding, credit facility	5,772,000
Revolving Credit Facility
Long-term Debt, by Maturity [Abstract]
Maximum allowed unrestricted cash and cash equivalents			$ 180,000,000
Revolving Credit Facility | Secured Debt | ABL Credit Facility
Debt Instrument [Line Items]
Outstanding borrowings	44,900,000	$ 0
Outstanding, credit facility	$ 15,100,000
Interest rate (as a percent)	4.30%
Long-term Debt, by Maturity [Abstract]
2020	$ 44,900,000
2021	0
2022	0
2023	0
2024	0
Later	0
Maximum allowed unrestricted cash and cash equivalents	$ 180,000,000