Debt - Convertible Senior Notes Due 2029 (Details)				1 Months Ended	3 Months Ended			6 Months Ended
	Dec. 12, 2022 day $ / shares	May 14, 2018 USD ($) day $ / shares	Jul. 05, 2017 USD ($) $ / shares	Dec. 31, 2022 USD ($)	Mar. 31, 2024 USD ($) $ / shares	Mar. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Mar. 31, 2024 USD ($) $ / shares	Mar. 31, 2023 USD ($)
Debt Instrument [Line Items]
Loss on extinguishment of debt | $							$ 3,500,000	$ 0	$ 3,545,000
2029 Convertible Notes | Common Class A
Debt Instrument [Line Items]
Conversion rate per $1,000 principal amount				0.0890313
2029 Convertible Notes | Senior Notes
Debt Instrument [Line Items]
Stated interest rate	3.75%			3.75%			3.75%
Principle amount | $				$ 230,000,000			$ 230,000,000
Effective interest rate					4.28%			4.28%
Conversion price, per share (in dollars per share) | $ / shares	$ 11.23
2029 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%
2029 Convertible Notes | Senior Notes | Debt Conversion, Condition One | Debt Instrument, Redemption, Period 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%
Repurchase price, percent of principal amount	100.00%
2029 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
2024 Convertible Notes | Common Class A
Debt Instrument [Line Items]
Conversion rate per $1,000 principal amount			0.1
2024 Convertible Notes | Senior Notes
Debt Instrument [Line Items]
Stated interest rate			2.875%
Principle amount | $			$ 143,750,000
Conversion price, per share (in dollars per share) | $ / shares			$ 10.00		$ 10.00			$ 10.00
Loss on extinguishment of debt | $					$ 0	$ 0		$ 0	8,935,000
2024 Convertible Notes | Notes Repurchases
Debt Instrument [Line Items]
Repurchased principal amount | $				109,400,000			109,400,000
Repurchase price | $				117,500,000			117,500,000
2025 Convertible Notes | Senior Notes
Debt Instrument [Line Items]
Stated interest rate		2.375%
Principle amount | $		$ 172,500,000
Conversion rate per $1,000 principal amount		0.0628931
Conversion price, per share (in dollars per share) | $ / shares		$ 15.90
Loss on extinguishment of debt | $					$ 0	$ 0		$ 0	$ (5,389,000)
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
2025 Convertible Notes | Notes Repurchases
Debt Instrument [Line Items]
Repurchased principal amount | $				69,100,000			69,100,000
Repurchase price | $				$ 62,900,000			$ 62,900,000