Debt (Narrative) (Details)		3 Months Ended			12 Months Ended
		Dec. 31, 2021 USD ($)	Mar. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2022 USD ($) facility		Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Debt Instrument [Line Items]
Maximum hedging reserve					$ 1,000,000
Senior notes		$ 792,500,000			794,500,000		$ 792,500,000
Repayments of senior notes					0		0	$ 401,800,000
Loss on extinguishment of debt		1,800,000	$ 7,400,000		0		0	7,400,000
Debt covenants					$ 1
Revolving Secured Line Of Credit [Member]
Debt Instrument [Line Items]
Debt maturity date					Jun. 22, 2025
Line of credit facility	[1]				$ 410,000,000
Line of credit facility decrease in maximum borrowing capacity					$ 25,000,000
Percentage of net book value of loans					80.00%
Warehouse Facilities [Member]
Debt Instrument [Line Items]
Percentage of net book value of loans					80.00%
Number of warehouse facilities | facility					5
Debt financing amount					$ 1,175,000,000
Monthly servicing fee per financing					6.00%
Monthly Servicing Fee Per Financing on Newer Deals					4.00%
Warehouse Facility II [Member]
Debt Instrument [Line Items]
Debt maturity date	[2],[3]				Apr. 30, 2024
Debt financing amount		$ 400,000,000.0			$ 400,000,000.0	[2],[4]	$ 400,000,000.0
Interest rate		0.00%			0.00%		0.00%
Warehouse Facility IV [Member]
Debt Instrument [Line Items]
Debt maturity date	[2],[3]				May 20, 2025
Debt financing amount		$ 300,000,000.0			$ 300,000,000.0	[2],[4]	$ 300,000,000.0
Interest rate		0.00%			0.00%		0.00%
Warehouse Facility V [Member]
Debt Instrument [Line Items]
Debt maturity date	[2],[5]				Dec. 29, 2025
Debt financing amount		$ 125,000,000.0			$ 200,000,000.0	[2],[4]	$ 125,000,000.0
Interest rate		0.00%			0.00%		0.00%
Warehouse Facility VI [Member]
Debt Instrument [Line Items]
Debt maturity date	[2],[3]				Sep. 30, 2024
Debt financing amount	[2]				$ 75,000,000.0
Interest rate		0.00%			0.00%		0.00%
2021 Senior Notes [Member]
Debt Instrument [Line Items]
Senior notes				$ 300,000,000				$ 300,000,000
Interest rate				6.125%				6.125%
Repayments of senior notes			$ 151,800,000	$ 148,200,000
2023 Senior Notes [Member]
Debt Instrument [Line Items]
Senior notes		$ 250,000,000					$ 250,000,000
Interest rate		7.375%					7.375%
2024 Senior Notes [Member]
Debt Instrument [Line Items]
Debt maturity date					Dec. 31, 2024
Debt financing amount					$ 400,000,000.0
Senior notes		$ 400,000,000.0			$ 400,000,000		$ 400,000,000.0
Interest rate		5.125%			5.125%		5.125%
2026 Senior Notes [Member]
Debt Instrument [Line Items]
Debt maturity date					Mar. 15, 2026
Debt financing amount					$ 400,000,000.0
Senior notes		$ 400,000,000.0			$ 400,000,000.0		$ 400,000,000.0
Interest rate		6.625%			6.625%		6.625%
Mortgage [Member]
Debt Instrument [Line Items]
Debt maturity date	[2]				Aug. 06, 2028
Debt financing amount	[2]				$ 9,000,000.0
Interest rate		1.60%			5.46%		1.60%
Warehouse Facility VIII [Member]
Debt Instrument [Line Items]
Debt maturity date	[2],[3]				Sep. 01, 2024
Debt financing amount		$ 200,000,000.0			$ 200,000,000.0	[2],[4]	$ 200,000,000.0
Interest rate		0.00%			0.00%		0.00%
Term ABS Financing [Member]
Debt Instrument [Line Items]
Monthly servicing fee per financing					6.00%
Monthly Servicing Fee Per Financing on Newer Deals					4.00%
Term ABS 2021-2 [Member]
Debt Instrument [Line Items]
Debt maturity date	[2],[3]				Feb. 15, 2023
Debt financing amount	[2]				$ 500,000,000.0
Interest rate		1.12%			1.12%		1.12%
Term ABS 2021-3 [Member]
Debt Instrument [Line Items]
Debt maturity date	[2],[3]				May 15, 2023
Debt financing amount	[2]				$ 450,000,000.0
Interest rate		1.14%			1.14%		1.14%
Term ABS 2021-4 [Member]
Debt Instrument [Line Items]
Debt maturity date	[2],[3]				Oct. 16, 2023
Debt financing amount	[2]				$ 250,100,000
Interest rate		1.44%			1.44%		1.44%
LIBOR [Member] | Warehouse Facility II [Member]
Debt Instrument [Line Items]
Basis spread on variable rate	[4]				175.00%
Prime Rate [Member] | Revolving Secured Line Of Credit [Member]
Debt Instrument [Line Items]
Basis spread on variable rate					87.50%
BSBY [Member] | Revolving Secured Line Of Credit [Member]
Debt Instrument [Line Items]
Basis spread on variable rate					187.50%
BSBY [Member] | Warehouse Facility VI [Member]
Debt Instrument [Line Items]
Basis spread on variable rate	[4]				200.00%
BSBY [Member] | Mortgage [Member]
Debt Instrument [Line Items]
Basis spread on variable rate					150.00%

[1] The amount of the facility will decrease by $25.0 million on June 22, 2023.

[2] Financing made available only to a specified subsidiary of the Company.

[3] Represents the revolving maturity date. The outstanding balance will amortize after the revolving maturity date based on the cash flows of the pledged assets.

[4] Interest rate cap agreements are in place to limit the exposure to increasing interest rates.

[5] Represents the revolving maturity date. The outstanding balance will amortize after the revolving maturity date and any amounts remaining on December 27, 2027 will be due on that date.