Stock-Based Compensation - Redwood Holdco Management Incentive Plan (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost	$ 1,994	$ 16	$ 156
Redwood Holdco Management Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost	$ 1,000	$ 0	$ 200

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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