Principles of Consolidation - Securitization Activity Related to Unconsolidated Variable Interest Entity's Sponsored by Redwood (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Variable Interest Entity [Line Items]
MSRs recognized			$ 36,834	$ 11,976
Variable Interest Entity, Not Primary Beneficiary
Variable Interest Entity [Line Items]
Principal balance of loans transferred	$ 699,655	$ 347,305	1,038,451	347,305
MSRs recognized	6,002	2,186	7,874	2,186
Variable Interest Entity, Not Primary Beneficiary | Trading Securities
Variable Interest Entity [Line Items]
Securities retained, at fair value	29,966	69,563	33,389	69,563
Variable Interest Entity, Not Primary Beneficiary | Available-for-sale Securities
Variable Interest Entity [Line Items]
Securities retained, at fair value	$ 3,450	$ 20,428	$ 6,309	$ 20,428