Equity Compensation Plans - Unrecognized Compensation Cost (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($)
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized [Roll Forward]
Unrecognized compensation cost at beginning of period	$ 32,328
Equity grants	20,800
Performance-based valuation adjustment	(7,352)
Equity grant forfeitures	(8,075)
Equity compensation expense	(10,037)
Unrecognized Compensation Cost at End of Period	27,664
Restricted Stock Awards
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized [Roll Forward]
Unrecognized Compensation Cost at End of Period	1,000
Restricted Stock Units
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized [Roll Forward]
Unrecognized Compensation Cost at End of Period	4,000
Deferred Stock Units
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized [Roll Forward]
Unrecognized Compensation Cost at End of Period	18,000
Performance Stock Units
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized [Roll Forward]
Unrecognized Compensation Cost at End of Period	6,000
Redwood Incentive Plan | Restricted Stock Awards
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized [Roll Forward]
Unrecognized compensation cost at beginning of period	1,990
Equity grants	0
Performance-based valuation adjustment	0
Equity grant forfeitures	(531)
Equity compensation expense	(895)
Unrecognized Compensation Cost at End of Period	564
Redwood Incentive Plan | Restricted Stock Units
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized [Roll Forward]
Unrecognized compensation cost at beginning of period	3,534
Equity grants	3,465
Performance-based valuation adjustment	0
Equity grant forfeitures	(2,163)
Equity compensation expense	(1,296)
Unrecognized Compensation Cost at End of Period	3,540
Redwood Incentive Plan | Deferred Stock Units
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized [Roll Forward]
Unrecognized compensation cost at beginning of period	17,858
Equity grants	12,261
Performance-based valuation adjustment	0
Equity grant forfeitures	(4,733)
Equity compensation expense	(7,620)
Unrecognized Compensation Cost at End of Period	17,766
Redwood Incentive Plan | Performance Stock Units
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized [Roll Forward]
Unrecognized compensation cost at beginning of period	8,946
Equity grants	4,937
Performance-based valuation adjustment	(7,352)
Equity grant forfeitures	(648)
Equity compensation expense	(89)
Unrecognized Compensation Cost at End of Period	5,794
Employee Stock Purchase Plan
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized [Roll Forward]
Unrecognized compensation cost at beginning of period	0
Equity grants	137
Performance-based valuation adjustment	0
Equity grant forfeitures	0
Equity compensation expense	(137)
Unrecognized Compensation Cost at End of Period	$ 0