Leases and Other Commitments - Purchase Commitments (Details)	12 Months Ended
	Mar. 31, 2020 USD ($)
Future commitments
Outstanding purchase orders	$ 361,881,000
Remaining commitment	185,969,000
Contract Value	$ 204,985,000
Minimum
Future commitments
Advance purchase period	2 years
Maximum
Future commitments
Advance purchase period	9 months
Sheepskin
Future commitments
Long-term purchase commitment period	2 years
Advance deposit	$ 8,322,000
Purchase Commitment One
Future commitments
Remaining commitment	33,205,000
Contract Value	45,600,000
Purchase Commitment Two
Future commitments
Remaining commitment	26,671,000
Contract Value	27,350,000
Purchase Commitment Three
Future commitments
Remaining commitment	50,460,000
Contract Value	50,460,000
Purchase Commitment Four
Future commitments
Remaining commitment	5,806,000
Contract Value	8,906,000
Purchase Commitment Five
Future commitments
Remaining commitment	39,983,000
Contract Value	42,825,000
Purchase Commitment Six
Future commitments
Remaining commitment	29,844,000
Contract Value	29,844,000
Other Purchase Commitment
Future commitments
Long-term purchase commitment	$ 46,059,000