Commitments and Contingencies - Additional Information (Details)		12 Months Ended
	Jul. 15, 2010 Plaintiff	Dec. 31, 2017 USD ($) loan lease repurchase_request	Dec. 31, 2016 USD ($) loan repurchase_request	Dec. 31, 2015 USD ($) loan	Dec. 23, 2009
Loss Contingencies [Line Items]
Number of non-cancelable leases | lease		4
Lease expiration year		2028
Future lease commitments with expiration date		$ 17,591,000
Operating lease expense		2,000,000	$ 3,000,000	$ 3,000,000
Unamortized leasehold improvements		100,000
Leasehold amortization expense (less than)		100,000	100,000	$ 100,000
Loss contingency accrual (less than)		100,000
Guarantee obligations		19,487,000	21,668,000
Guarantee obligation, credit reserve		10,000,000
SPE, assets		48,000,000	49,000,000
SPE, liabilities		19,000,000	22,000,000
Residential loan and MSR repurchase reserve		$ 4,916,000	$ 5,432,000
Residential loans repurchase requests | repurchase_request		17	59
Residential loans, number of loans repurchased | loan		1	1	0
Residential loans repurchase provision (reversal)		$ (300,000)	$ (1,000,000)	$ 3,000,000
Residential loans repurchased during period		200,000	100,000	0
Aggregate amount of loss contingency reserves		2,000,000	2,000,000
Schwab
Loss Contingencies [Line Items]
Number of other named defendants along with SRF | Plaintiff	26
Residential Loans
Loss Contingencies [Line Items]
Principal amount outstanding on loans securitized		1,410,000,000	830,000,000
Loans held as assets amount in foreclosure		1,000,000
Other Income
Loss Contingencies [Line Items]
Fee income from risk sharing agreement		3,000,000	5,000,000	3,000,000
Mortgage Banking And Investment Activities
Loss Contingencies [Line Items]
Market valuation changes in fair value of guarantee asset		(1,000,000)	$ (1,000,000)	$ (2,000,000)
Guarantee Obligations
Loss Contingencies [Line Items]
Original principal balance of loans sold subject to risk sharing agreement		3,190,000,000
Potential future payments on risk sharing agreements		44,000,000
Principal amount outstanding on loans securitized		$ 2,100,000,000
FICO credit score		758
Loan to value ratio		77.00%
Guarantee Obligations | Financing Receivables, Equal to Greater than 90 Days Past Due
Loss Contingencies [Line Items]
Loans past due		$ 8,000,000
Residential | Sequoia Entities | FHLB Seattle
Loss Contingencies [Line Items]
Statutory interest rate per annum					8.00%
Original principal amount of securities		133,000,000
Debt instrument principal payment amount		125,000,000
Debt instrument interest payment amount		11,000,000
Residential | Sequoia Entities | Schwab
Loss Contingencies [Line Items]
Original principal amount of securities		15,000,000
Principal balance of securities		14,000,000
Debt instrument interest amount		$ 1,000,000