Debt - Valuation of Debt (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Mar. 31, 2023
Fair Value
Debt Instrument [Line Items]
Fair value of senior notes and equipment financing	$ 822,004	$ 848,496
Fair Value | Equipment Financing
Debt Instrument [Line Items]
Fair value of senior notes and equipment financing	13,599	17,921
Carrying Value
Debt Instrument [Line Items]
Fair value of senior notes and equipment financing	864,179	868,638
Carrying Value | Equipment Financing
Debt Instrument [Line Items]
Fair value of senior notes and equipment financing	14,179	18,638
Senior Notes due 2027 | Fair Value | Senior Notes
Debt Instrument [Line Items]
Fair value of senior notes and equipment financing	328,395	333,970
Senior Notes due 2027 | Carrying Value | Senior Notes
Debt Instrument [Line Items]
Fair value of senior notes and equipment financing	350,000	350,000
Senior Notes due 2030 | Fair Value | Senior Notes
Debt Instrument [Line Items]
Fair value of senior notes and equipment financing	480,010	496,605
Senior Notes due 2030 | Carrying Value | Senior Notes
Debt Instrument [Line Items]
Fair value of senior notes and equipment financing	$ 500,000	$ 500,000