Fair Value - Components of Net Gains on Sales of Loans (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended
Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2012
Fair Value Disclosures [Abstract]
Gains on sales of loans	$ 8,338	$ 83,864
Unrealized gains on loans held for sale	67,970	65,699
Net fair value gains (losses) on derivatives	(11,927)	184,503
Capitalized servicing rights	80,550	118,145
Provision for repurchases	(3,387)	(5,568)
Interest income	12,166	21,427
Other		34
Net gains on sales of loans	$ 153,710	$ 468,104

Amount of realized and unrealized gain (loss) of derivative instruments not designated or qualifying as hedging instruments.

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The gains (losses) included in earnings that represent the difference between the sale price and the carrying value of loans made to finance real estate acquisitions. This element refers to the gain (loss) and not to the cash proceeds of the sale. This element is a noncash adjustment to net income when calculating net cash generated by operating activities using the indirect method.

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The increase (decrease) during the reporting period in the value of mortgage loans that are held with the intention to sell or be securitized in the near future.

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The amount of interest and fee income earned from loans held-for-sale, including mortgage loans, and interest earned from direct financing and sales-type leases held-for-sale.

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Amount of expense related to other loss.

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Reflects, by transferred financial asset type, the amount of sales proceeds in excess of or deficient from the sum of the carrying amounts of transferred financial assets plus transaction costs, including those transactions in which the seller/transferor has continuing involvement with the financial assets that have been transferred.

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The value of new servicing assets, subsequently measured at fair value, acquired or created during the current period through purchases or from transfers of financial assets.

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Other changes in mortgage loans held for sale.

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