Borrowings - Narrative (Details)				1 Months Ended		3 Months Ended		9 Months Ended
	Sep. 19, 2024 day	Sep. 16, 2024	Aug. 20, 2021 USD ($) day $ / shares	Nov. 07, 2024 USD ($)	Sep. 30, 2024 USD ($) $ / shares	Sep. 30, 2024 USD ($) $ / shares	Sep. 30, 2023 USD ($)	Sep. 30, 2024 USD ($) $ / shares	Sep. 30, 2023 USD ($)	Apr. 24, 2024 USD ($)	Apr. 23, 2024 USD ($)
Schedule of Borrowings [Line Items]
Repayment of warehouse borrowings								$ 293,179,000	$ 514,792,000
Proceeds from convertible notes issuance, net of debt issuance costs paid to lender								423,002,000	0
Gain on debt extinguishment						$ 33,361,000	$ 0	33,361,000	0
Payment for debt repurchased								325,344,000	0
Purchase of capped calls								40,883,000	0
Convertible Debt
Schedule of Borrowings [Line Items]
Redemption price (in percent)	100.00%
Trading days | day	20
Consecutive trading days | day	30
Conversion price maximum threshold	130.00%
Interest expense						0	0	0	0
Amortization of debt issuance costs						0	$ 0	0	$ 0
Convertible Debt | Conversion Period One
Schedule of Borrowings [Line Items]
Trading days | day			20
Consecutive trading days | day			30
Conversion price maximum threshold			130.00%
Convertible Debt | Conversion Period Two
Schedule of Borrowings [Line Items]
Trading days | day			5
Consecutive trading days | day			5
Percentage of the last reported sale price			98.00%
ULT Warehouse Credit Facility - UnCommitted | Revolving Credit Facility
Schedule of Borrowings [Line Items]
Maximum borrowing capacity					$ 150,000,000	150,000,000		150,000,000		$ 150,000,000	$ 75,000,000
ULT Warehouse Credit Facility - UnCommitted | Revolving Credit Facility | Subsequent Event
Schedule of Borrowings [Line Items]
Repayment of warehouse borrowings				$ 26,800,000
2026 ("Notes") | Convertible Debt
Schedule of Borrowings [Line Items]
Aggregate principal amount			$ 661,300,000
Stated interest rate			0.25%
Additional repurchased amount					27,900,000	27,900,000		27,900,000
Repurchase amount					334,200,000	334,200,000		334,200,000
Gain on debt extinguishment						33,400,000		33,400,000
Initial conversion rate (in shares)			0.0035056
Initial conversion price (in dollars per share) | $ / shares			$ 285.26
Gross debt issuance cost			$ 15,700,000
Effective interest rate			0.70%
Payment for debt repurchased								362,121,000
2029 Notes | Convertible Debt
Schedule of Borrowings [Line Items]
Aggregate principal amount					$ 431,300,000	$ 431,300,000		$ 431,300,000
Stated interest rate					2.00%	2.00%		2.00%
Proceeds from convertible notes issuance, net of debt issuance costs paid to lender					$ 302,400,000			$ 431,250,000
Initial conversion rate (in shares)		0.0219029
Initial conversion price (in dollars per share) | $ / shares					$ 45.66	$ 45.66		$ 45.66
Gross debt issuance cost			$ 10,400,000
Effective interest rate					2.50%	2.50%		2.50%