Commitments and Contingencies - Additional Information (Detail) $ in Thousands		3 Months Ended	9 Months Ended
	Jul. 15, 2010 Plaintiff	Sep. 30, 2015 USD ($) lease	Sep. 30, 2015 USD ($) loan lease repurchase_request	Sep. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)
Loss Contingencies [Line Items]
Number of noncancelable leases | lease		9	9
Operating lease expiration dates			2021
Future lease commitments with expiration date		$ 10,927	$ 10,927
Operating lease expense			$ 2,000	$ 2,000
Risk-sharing arrangement term (years)			10 years
Special Purpose Entities (SPEs) assets		36,000	$ 36,000		$ 19,000
Special Purpose Entities (SPEs) liabilities		16,000	16,000		7,000
Residential repurchase reserve		5,768	$ 5,768		3,724
Residential repurchase requests | repurchase_request			69
Residential repurchase, number of loans repurchased | loan			1
Residential repurchase provisions recorded		1,000	$ 2,000
Aggregate amount of loss contingency reserves		2,000	2,000		$ 2,000
Schwab
Loss Contingencies [Line Items]
Number of other named defendants along with SRF | Plaintiff	26
Guarantee Obligations
Loss Contingencies [Line Items]
Unpaid principal amount on loans		$ 1,800,000	$ 1,800,000
Weighted average original Fair Isaac Corporation (FICO) score		760	760
Weighted average original loan-to-value (LTV)		76.00%	76.00%
Potential future payments on loans		$ 19,000	$ 19,000
Guarantee Obligations | Financing Receivables, Equal To Greater Than 30 Days Past Due
Loss Contingencies [Line Items]
Percent of loans in reference portfolio that are past due			100000000.00%
Guarantee Obligations | Financing Receivables, Equal to Greater than 90 Days Past Due
Loss Contingencies [Line Items]
Percent of loans in reference portfolio that are past due			100000000.00%
Residential | Sequoia | FHLB Seattle
Loss Contingencies [Line Items]
Statutory interest rate per annum		8.00%	8.00%
Original principal amount of securities		$ 133,000	$ 133,000
Debt instrument principal payment amount			120,000
Debt instrument interest payment amount			11,000
Residential | Sequoia | Schwab
Loss Contingencies [Line Items]
Original principal amount of securities		15,000	15,000
Principal balance of securities		13,000	13,000
Debt instrument interest amount		1,000	1,000
Other income
Loss Contingencies [Line Items]
Fee income from risk sharing agreement		1,000	1,000
Mortgage banking and investment activities
Loss Contingencies [Line Items]
Market valuation changes in fair value of guarantee asset (less than for three months ending June 30, 2015)		$ (1,000)	$ (2,000)
Minimum
Loss Contingencies [Line Items]
Percentage of losses assumed on pool of loans sold		1.00%
Maximum
Loss Contingencies [Line Items]
Percentage of losses assumed on pool of loans sold		2.25%