Mortgage Banking and Invetsment Activities, Net (Detail) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Mortgage Loans on Real Estate [Line Items]
Hedging allocation	$ 0
Total investment activities	(21,357)	$ (10,202)	$ (5,747)
Mortgage banking and investment activities, net	(10,385)	24,792	96,785
Residential Mortgage Banking Activities
Mortgage Loans on Real Estate [Line Items]
Hedging allocation	1,120	0	0
Other income, net	4,040	3,468	48
Mortgage banking activities, net	8,268	21,554	79,431
Commercial Mortgage Banking Activities
Mortgage Loans on Real Estate [Line Items]
Net gains on commercial loan sales	0	0	11,031
Other income, net	450	541	0
Mortgage banking activities, net	2,704	13,440	23,101
Investment Activities
Mortgage Loans on Real Estate [Line Items]
Changes in fair value of risk management derivatives	(8,557)	(7,792)	223
Hedging allocation	(1,120)	0	0
Residential loans at fair value \| Residential Mortgage Banking Activities
Mortgage Loans on Real Estate [Line Items]
Changes in fair value of assets	3,712	51,311	(10,455)
Real estate securities \| Residential Mortgage Banking Activities
Mortgage Loans on Real Estate [Line Items]
Changes in fair value of assets	(15,261)	(23,839)	42,451
Real estate securities \| Investment Activities
Mortgage Loans on Real Estate [Line Items]
Changes in fair value of assets	(2,265)	(923)	(5,357)
Risk management derivatives \| Residential Mortgage Banking Activities
Mortgage Loans on Real Estate [Line Items]
Changes in fair value of assets	14,657	(9,386)	47,387
Risk management derivatives \| Commercial Mortgage Banking Activities
Mortgage Loans on Real Estate [Line Items]
Changes in fair value of risk management derivatives	(8,011)	(7,890)	3,376
Commercial Loans at Fair Value \| Commercial Mortgage Banking Activities
Mortgage Loans on Real Estate [Line Items]
Changes in fair value of assets	10,265	20,789	8,694
Residential Loans Held for Investment \| Investment Activities
Mortgage Loans on Real Estate [Line Items]
Changes in fair value of assets	(6,337)	(697)	0
Investments In Consolidated Variable Interest Entity \| Investment Activities
Mortgage Loans on Real Estate [Line Items]
Changes in fair value of assets	(1,192)	(894)	(613)
Risk Sharing Investments \| Investment Activities
Mortgage Loans on Real Estate [Line Items]
Changes in fair value of assets	$ (1,886)	$ 104	$ 0

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Investment Banking Activities, Net

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The net income attributable to mortgage banking activities. This includes market valuations related to residential and commercial loans, Sequoia IOs, and mortgage banking derivatives, as well as realized gains or losses associated with mortgage loan sales.

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Mortgage Banking And Investment Activities

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Fee and commission revenue earned from sources not otherwise specified in the existing taxonomy.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.13)
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Gain (loss) incurred in hedging activities.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4A
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The net gain (loss) resulting from a sale of loans, including adjustments to record loans classified as held-for-sale at the lower-of-cost-or-market and fair value adjustments to loan held for investment purposes.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 225
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Amount of unrealized gain (loss) related to the fair value of price risk derivatives designated as fair value hedging instruments, as offset by the gain (loss) on the hedged item to the extent that the fair value hedge is determined to be effective.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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