Principles of Consolidation - Key Assumptions and Sensitivity Analysis for Assets Retained from Unconsolidated Variable Interest Entity's Sponsored by Redwood (Details) - Variable Interest Entity, Not Primary Beneficiary - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
MSRs
Sensitivity Analysis of Fair Value of Interests Continued to be Held by Transferor, Servicing Assets or Liabilities, Impact of Adverse Change in Assumption [Line Items]
Fair value	$ 58,800	$ 56,984
Expected life (in years)	7 years	7 years
Prepayment speed assumption (annual CPR) (as a percent)	11.00%	11.00%
Decrease in fair value from:
10% adverse change	$ 2,226	$ 2,868
25% adverse change	$ 5,284	$ 6,119
Impact of adverse change in prepayment speed (as a percent)	25.00%	25.00%
Discount rate assumption (as a percent)	11.00%	11.00%
Decrease in fair value from:
100 basis point increase	$ 2,088	$ 2,711
200 basis point increase	$ 4,032	$ 4,745
Impact on discount rate of basis point increase (as a percent)	1.00%	1.00%
Decrease in fair value from:
Impact of adverse change in expected credit losses (as a percent)	25.00%	25.00%
Senior Securities
Sensitivity Analysis of Fair Value of Interests Continued to be Held by Transferor, Servicing Assets or Liabilities, Impact of Adverse Change in Assumption [Line Items]
Fair value	$ 26,618	$ 248,570
Expected life (in years)	6 years	5 years
Prepayment speed assumption (annual CPR) (as a percent)	8.00%	10.00%
Decrease in fair value from:
10% adverse change	$ 1,075	$ 2,042
25% adverse change	$ 2,569	$ 4,810
Impact of adverse change in prepayment speed (as a percent)	25.00%	25.00%
Discount rate assumption (as a percent)	8.00%	5.00%
Decrease in fair value from:
100 basis point increase	$ 1,105	$ 10,029
200 basis point increase	$ 2,128	$ 19,365
Impact on discount rate of basis point increase (as a percent)	1.00%	1.00%
Credit loss assumption (as a percent)	0.25%	0.25%
Decrease in fair value from:
10% higher losses	$ 19	$ 35
25% higher losses	$ 49	$ 86
Impact of adverse change in expected credit losses (as a percent)	25.00%	25.00%
Subordinate Securities
Sensitivity Analysis of Fair Value of Interests Continued to be Held by Transferor, Servicing Assets or Liabilities, Impact of Adverse Change in Assumption [Line Items]
Fair value	$ 249,317	$ 282,842
Expected life (in years)	12 years	12 years
Prepayment speed assumption (annual CPR) (as a percent)	12.00%	12.00%
Decrease in fair value from:
10% adverse change	$ 997	$ 901
25% adverse change	$ 2,494	$ 2,278
Impact of adverse change in prepayment speed (as a percent)	25.00%	25.00%
Discount rate assumption (as a percent)	6.00%	6.00%
Decrease in fair value from:
100 basis point increase	$ 19,574	$ 21,981
200 basis point increase	$ 36,574	$ 41,156
Impact on discount rate of basis point increase (as a percent)	1.00%	1.00%
Credit loss assumption (as a percent)	0.25%	0.25%
Decrease in fair value from:
10% higher losses	$ 1,174	$ 1,244
25% higher losses	$ 2,933	$ 3,129
Impact of adverse change in expected credit losses (as a percent)	25.00%	25.00%
Interest Only Securities
Sensitivity Analysis of Fair Value of Interests Continued to be Held by Transferor, Servicing Assets or Liabilities, Impact of Adverse Change in Assumption [Line Items]
Fair value	$ 27,000	$ 31,000