Borrowings - Narrative (Details) $ / shares in Units, shares in Millions		1 Months Ended		9 Months Ended
	Aug. 20, 2021 USD ($) day option_to_extend $ / shares shares	Aug. 31, 2022 USD ($)	May 31, 2020 USD ($)	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)	Dec. 31, 2021 USD ($)
Schedule of Borrowings [Line Items]
Outstanding borrowings				$ 930,978,000		$ 709,787,000
Purchase of capped calls				$ 0	$ 58,523,000
ULT Warehouse Credit Facility | Revolving Credit Facility
Schedule of Borrowings [Line Items]
Maximum borrowing capacity			$ 175,000,000
Redemption price (in percent)			100.00%
Maximum advance rate (in percent)				72.50%		85.00%
ULT Warehouse Credit Facility | Revolving Credit Facility | Variable Interest Entity, Primary Beneficiary
Schedule of Borrowings [Line Items]
Outstanding borrowings				$ 100,523,000		$ 48,030,000
ULT Warehouse Credit Facility | Minimum | Revolving Credit Facility
Schedule of Borrowings [Line Items]
Monthly unused fee (in percent)			0.20%
ULT Warehouse Credit Facility | Maximum | Revolving Credit Facility
Schedule of Borrowings [Line Items]
Monthly unused fee (in percent)			1.00%
ULT Warehouse Credit Facility - Committed | Revolving Credit Facility
Schedule of Borrowings [Line Items]
Maximum borrowing capacity			$ 100,000,000
ULT Warehouse Credit Facility - Uncommitted | Revolving Credit Facility
Schedule of Borrowings [Line Items]
Maximum borrowing capacity			$ 75,000,000
UAWT Warehouse Credit Facility | Revolving Credit Facility
Schedule of Borrowings [Line Items]
Monthly unused fee (in percent)		0.50%
Maximum advance rate (in percent)				82.50%		82.50%
UAWT Warehouse Credit Facility | Revolving Credit Facility | Primary Beneficiary
Schedule of Borrowings [Line Items]
Maximum borrowing capacity		$ 200,000,000
UAWT Warehouse Credit Facility | Revolving Credit Facility | Variable Interest Entity, Primary Beneficiary
Schedule of Borrowings [Line Items]
Outstanding borrowings				$ 169,205,000		$ 0
2026 ("Notes")
Schedule of Borrowings [Line Items]
Outstanding borrowings				661,250,000		661,250,000
Convertible notes payable				649,200,000		646,900,000
Purchase of capped calls	$ 58,500,000
Initial conversion price (in dollars per share) | $ / shares	$ 285.26
Initial cap price (in dollars per share) | $ / shares	$ 400.36
Capped call cover (in shares) | shares	2.3
2026 ("Notes") | Fair Value, Inputs, Level 2
Schedule of Borrowings [Line Items]
Fair value of convertible senior notes				$ 374,300,000		$ 627,500,000
2026 ("Notes") | Convertible Debt
Schedule of Borrowings [Line Items]
Aggregate principal amount	$ 661,300,000
Stated interest rate	0.25%
Additional aggregate principal	$ 86,300,000
Net proceeds from sale of the notes	$ 645,500,000
Initial conversion rate (in shares)	0.003506
Initial conversion price (in dollars per share) | $ / shares	$ 285.26
Percent of the principal amount	100.00%
2026 ("Notes") | Convertible Debt | Conversion Period One
Schedule of Borrowings [Line Items]
Trading days | day	20
Consecutive trading days | option_to_extend	30
Conversion price maximum threshold	130.00%
2026 ("Notes") | Convertible Debt | Conversion Period Two
Schedule of Borrowings [Line Items]
Trading days | option_to_extend	5
Consecutive trading days | option_to_extend	5
Percentage of the last reported sale price	98.00%
2026 ("Notes") | Convertible Debt | Conversion Period Three
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%
Gross debt issuance cost	$ 15,700,000
Effective interest rate				0.70%
Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate | ULT Warehouse Credit Facility | Minimum | Revolving Credit Facility
Schedule of Borrowings [Line Items]
Basis spread on variable rate (in percent)			1.90%
Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate | ULT Warehouse Credit Facility | Maximum | Revolving Credit Facility
Schedule of Borrowings [Line Items]
Basis spread on variable rate (in percent)			328.00%
Weighted-Average Cost Of Commercial Paper Notes Issued By The Lender | UAWT Warehouse Credit Facility | Minimum | Revolving Credit Facility
Schedule of Borrowings [Line Items]
Basis spread on variable rate (in percent)		2.20%
Weighted-Average Cost Of Commercial Paper Notes Issued By The Lender | UAWT Warehouse Credit Facility | Maximum | Revolving Credit Facility
Schedule of Borrowings [Line Items]
Basis spread on variable rate (in percent)		3.50%