Fair Value of Financial Instruments - Portion of Net Gains (Losses) Attributable to Level 3 Assets and Liabilities Still Held Included in Net Income (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Loan Purchase Commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net gains (losses) attributable to level 3 liabilities still held included in net income		$ 1,707		$ 1,707
Commercial Secured Borrowings
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net gains (losses) attributable to level 3 liabilities still held included in net income	$ 2,713	1,759	$ 1,204	1,759
Asset-backed Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net gains (losses) attributable to level 3 liabilities still held included in net income	(3,552)		(6,498)
Residential Loans Held For Investment at Fair Value | Residential loans at Redwood
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net gains (losses) attributable to level 3 assets still held included in net income	(7,508)	11,755	(5,441)	11,964
Residential Loans Held For Investment at Fair Value | Residential loans at consolidated Sequoia entities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net gains (losses) attributable to level 3 assets still held included in net income	2,476	0	5,331	0
Guarantee Asset
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net gains (losses) attributable to level 3 assets still held included in net income	228	0	(700)	0
Commercial Loans at Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net gains (losses) attributable to level 3 assets still held included in net income	(1,565)	2,008	(56)	2,008
Trading Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net gains (losses) attributable to level 3 assets still held included in net income	4,601	(9,257)	(5,254)	(13,688)
Available-for-sale Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net gains (losses) attributable to level 3 assets still held included in net income	0	(264)	0	(377)
Mortgage servicing rights
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net gains (losses) attributable to level 3 assets still held included in net income	21,296	$ (4,974)	10,277	$ (7,236)
Loan Purchase Commitments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net gains (losses) attributable to level 3 liabilities still held included in net income	$ (3,810)		$ (1,826)