Fair Value - Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis Utilizing Significant Unobservable Inputs Reconciliation (Detail) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2017	Mar. 31, 2016
Assets
Fair Value, Beginning Balance	$ 12,245,112	$ 13,089,216
Total Gains (Losses) Included in Comprehensive Income (Loss)	11,789	(139,572)
Purchases and Other	43,580	73,657
Sales and Other	76
Originations/ Issuances	111,866	179,409
Settlements	(351,936)	(264,380)
Fair Value, Ending Balance	12,060,487	12,938,330
Liabilities
Fair Value, Beginning Balance	(11,027,667)	(11,347,792)
Total Gains (Losses) Included in Comprehensive Income (Loss)	(32,990)	(122,449)
Purchases and Other	0	0
Sales and Other	0
Originations/ Issuances	(154,315)	(202,947)
Settlements	425,985	305,107
Fair Value, Ending Balance	(10,788,987)	(11,368,081)
Freestanding Derivative Instruments \| Interest Rate Lock Commitments
Liabilities
Fair Value, Beginning Balance	(4,193)	(1,070)
Total Gains (Losses) Included in Comprehensive Income (Loss)	3,479	815
Purchases and Other	0	0
Sales and Other	0
Originations/ Issuances	0	0
Settlements	0	0
Fair Value, Ending Balance	(714)	(255)
Servicing Rights Related Liabilities
Liabilities
Fair Value, Beginning Balance		(117,000)
Total Gains (Losses) Included in Comprehensive Income (Loss)		3,294
Purchases and Other		0
Originations/ Issuances		0
Settlements		8,147
Fair Value, Ending Balance		(105,559)
Mortgage-Backed Debt Related to Non-Residual Trusts
Liabilities
Fair Value, Beginning Balance	(514,025)	(582,340)
Total Gains (Losses) Included in Comprehensive Income (Loss)	(8,559)	(6,932)
Purchases and Other	0	0
Sales and Other	0
Originations/ Issuances	0	0
Settlements	23,816	24,440
Fair Value, Ending Balance	(498,768)	(564,832)
HMBS Related Obligations
Liabilities
Fair Value, Beginning Balance	(10,509,449)	(10,647,382)
Total Gains (Losses) Included in Comprehensive Income (Loss)	(27,910)	(119,626)
Purchases and Other	0	0
Sales and Other	0
Originations/ Issuances	(154,315)	(202,947)
Settlements	402,169	272,520
Fair Value, Ending Balance	(10,289,505)	(10,697,435)
Reverse Loans
Assets
Fair Value, Beginning Balance	10,742,922	10,763,816
Total Gains (Losses) Included in Comprehensive Income (Loss)	42,612	154,834
Purchases and Other	43,134	54,020
Sales and Other	0
Originations/ Issuances	87,062	127,151
Settlements	(315,998)	(226,930)
Fair Value, Ending Balance	10,599,732	10,872,891
Mortgage Loans Related to Non-Residual Trusts
Assets
Fair Value, Beginning Balance	450,377	526,016
Total Gains (Losses) Included in Comprehensive Income (Loss)	12,502	5,163
Purchases and Other	0	0
Sales and Other	0
Originations/ Issuances	0	0
Settlements	(22,660)	(24,842)
Fair Value, Ending Balance	440,219	506,337
Charged-Off Loans
Assets
Fair Value, Beginning Balance	46,963	49,307
Total Gains (Losses) Included in Comprehensive Income (Loss)	14,591	14,376
Purchases and Other	0	0
Sales and Other	0
Originations/ Issuances	0	0
Settlements	(9,483)	(10,437)
Fair Value, Ending Balance	52,071	53,246
Liabilities
Gains from instrument-specific credit risk	10,100	10,900
Receivables Related to Non-Residual Trusts
Assets
Fair Value, Beginning Balance	15,033	16,542
Total Gains (Losses) Included in Comprehensive Income (Loss)	2,569	(467)
Purchases and Other	0	0
Sales and Other	0
Originations/ Issuances	0	0
Settlements	(3,754)	(1,957)
Fair Value, Ending Balance	13,848	14,118
Servicing Rights Carried at Fair Value
Assets
Fair Value, Beginning Balance	936,423	1,682,016
Total Gains (Losses) Included in Comprehensive Income (Loss)	(52,479)	(326,580)
Purchases and Other	446	19,637
Sales and Other	76
Originations/ Issuances	24,804	52,258
Settlements	0	0
Fair Value, Ending Balance	909,270	1,427,331
Freestanding Derivative Instruments \| Interest Rate Lock Commitments
Assets
Fair Value, Beginning Balance	53,394	51,519
Total Gains (Losses) Included in Comprehensive Income (Loss)	(8,006)	13,102
Purchases and Other	0	0
Sales and Other	0
Originations/ Issuances	0	0
Settlements	(41)	(214)
Fair Value, Ending Balance	$ 45,347	$ 64,407

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount of gain (loss) recognized in the income statement for financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of issuances of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of purchases of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of sale of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of settlement of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Fair value of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of gain (loss) recognized on the income statement for financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of purchases of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of sales of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Fair value of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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This item represents the estimated amount of gains or losses included in earnings during the period attributable to changes in instrument-specific credit risk arising from loans and other receivables held as assets.

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