Debt - Convertible Senior Notes Due 2025 (Details)	May 14, 2018 USD ($) day $ / shares	Mar. 31, 2024 USD ($)	Sep. 30, 2023 USD ($)	Mar. 31, 2023 USD ($)
Debt Instrument [Line Items]
Amount outstanding | $		$ 367,762,000	$ 367,762,000	$ 367,762,000
Senior Notes
Debt Instrument [Line Items]
Amount outstanding | $		367,762,000
2025 Convertible Notes | Senior Notes
Debt Instrument [Line Items]
Stated interest rate	2.375%
Principle amount | $	$ 172,500,000
Amount outstanding | $		$ 103,373,000
Effective interest rate		2.88%
Conversion rate per $1,000 principal amount	0.0628931
Conversion price, per share (in dollars per share) | $ / shares	$ 15.90
2025 Convertible Notes | Senior Notes | Debt Instrument, Redemption, Period One
Debt Instrument [Line Items]
Threshold consecutive trading days	30
Threshold percentage of stock price trigger	130.00%
Repurchase price, percent of principal amount	100.00%
2025 Convertible Notes | Senior Notes | Debt Conversion, Condition One
Debt Instrument [Line Items]
Threshold trading days (whether or not consecutive)	20
Threshold consecutive trading days	30
Threshold percentage of stock price trigger	130.00%
2025 Convertible Notes | Senior Notes | Debt Conversion, Condition Two
Debt Instrument [Line Items]
Threshold consecutive trading days	5
Threshold percentage of stock price trigger	98.00%
Business day threshold	5