Notes Payable to Related Parties - Additional Information (Details)			12 Months Ended
	Jun. 25, 2018 USD ($) Note	Jan. 31, 2018 USD ($) Note	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($) Note	Dec. 31, 2017 USD ($) Note
Related Party Transaction [Line Items]
Interest expense related parties			$ 0	$ 4,603,000	$ 3,478,000
Eldridge Industries, LLC
Related Party Transaction [Line Items]
Notes issued outstanding amount					230,000,000
Repayment of short-term note				384,000,000	$ 313,000,000
Warehouse Notes
Related Party Transaction [Line Items]
Number of short-term notes issued | Note					33
Notes issued during the year				154,000,000	$ 523,000,000
Notes issued outstanding amount			$ 0	$ 0
Number of notes repaid | Note					14
Number of notes issued | Note				20
Repayment on notes	$ 334,000,000	$ 50,000,000
Number of notes repaid in full | Note	36	3
Number of notes repaid in part | Note		1
Warehouse Notes | Maximum
Related Party Transaction [Line Items]
Accrued interest rate maturity period					1 year
Warehouse Notes | Maximum | LIBOR
Related Party Transaction [Line Items]
Debt instrument, base interest rates			2.76%
Warehouse Notes | Eldridge Industries, LLC
Related Party Transaction [Line Items]
Notes issued outstanding amount					$ 230,000,000
Repayment of short-term note				$ 384,000,000	$ 293,000,000
Warehouse Notes | Eldridge Industries, LLC | Minimum | LIBOR
Related Party Transaction [Line Items]
Debt instrument, base interest rates			2.14%
Short Term Notes | Eldridge Industries, LLC
Related Party Transaction [Line Items]
Number of additional short-term notes issued | Note					1
Notes issued outstanding amount					$ 20,000,000
Repayment of short-term note					$ 20,000,000
Debt instrument, base interest rates					8.00%