Fair Value of Financial Instruments - Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands		Dec. 31, 2017	Dec. 31, 2016
Assets
Trading securities		$ 968,844	$ 445,687
Available-for-sale securities		507,666	572,752
Derivative assets	[1]	15,718	36,595
MSR Fair Value	[1]	63,598	118,526
Pledged collateral		42,615	42,875
Liabilities
Derivative liabilities	[1]	63,081	66,329
Fair Value, Measurements, Recurring
Assets
Trading securities		968,844	445,687
Available-for-sale securities		507,666	572,752
Derivative assets		15,718	36,595
MSR Fair Value		63,598	118,526
Pledged collateral		42,615	42,875
FHLBC stock		43,393	43,393
Guarantee asset		2,869	4,092
Liabilities
Derivative liabilities		63,081	66,329
ABS issued		1,164,585	773,462
Fair Value, Measurements, Recurring | Residential Loans
Assets
Residential loans		5,114,317	3,886,845
Fair Value, Measurements, Recurring | Level 1
Assets
Trading securities		0	0
Available-for-sale securities		0	0
Derivative assets		134	8,300
MSR Fair Value		0	0
Pledged collateral		42,615	42,875
FHLBC stock		0	0
Guarantee asset		0	0
Liabilities
Derivative liabilities		3,808	5,609
ABS issued		0	0
Fair Value, Measurements, Recurring | Level 1 | Residential Loans
Assets
Residential loans		0	0
Fair Value, Measurements, Recurring | Level 2
Assets
Trading securities		0	0
Available-for-sale securities		0	0
Derivative assets		10,164	24,980
MSR Fair Value		0	0
Pledged collateral		0	0
FHLBC stock		43,393	43,393
Guarantee asset		0	0
Liabilities
Derivative liabilities		55,567	56,919
ABS issued		0	0
Fair Value, Measurements, Recurring | Level 2 | Residential Loans
Assets
Residential loans		0	0
Fair Value, Measurements, Recurring | Level 3
Assets
Trading securities		968,844	445,687
Available-for-sale securities		507,666	572,752
Derivative assets		5,420	3,315
MSR Fair Value		63,598	118,526
Pledged collateral		0	0
FHLBC stock		0	0
Guarantee asset		2,869	4,092
Liabilities
Derivative liabilities		3,706	3,801
ABS issued		1,164,585	773,462
Fair Value, Measurements, Recurring | Level 3 | Residential Loans
Assets
Residential loans		$ 5,114,317	$ 3,886,845

[1] Our consolidated balance sheets include assets of consolidated variable interest entities (“VIEs”) that can only be used to settle obligations of these VIEs and liabilities of consolidated VIEs for which creditors do not have recourse to Redwood Trust, Inc. or its affiliates. At December 31, 2017 and December 31, 2016, assets of consolidated VIEs totaled $1,259,774 and $798,317, respectively. At December 31, 2017 and December 31, 2016, liabilities of consolidated VIEs totaled $1,167,157 and $773,980, respectively. See Note 4 for further discussion.