Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Assets
Trading securities	$ 173,281	$ 124,555
Available-for-sale securities	1,671,786	1,558,306
MSRs	71,225	64,824
Derivative assets	7,514	7,787
Liabilities
Derivative liabilities	39,837	18,167
Commercial secured borrowings	66,692	0
Fair Value, Measurements, Recurring
Assets
Trading securities	173,281
Available-for-sale securities	1,671,786
MSRs	71,225
Derivative assets	7,514
Liabilities
Derivative liabilities	39,837
Commercial secured borrowings	66,692
Fair Value, Measurements, Recurring \| Residential Loans at Fair Value
Assets
Loans at fair value	1,106,239
Fair Value, Measurements, Recurring \| Commercial Loans at Fair Value
Assets
Loans at fair value	122,118
Fair Value, Measurements, Recurring \| Level 1
Assets
Derivative assets	3,295
Liabilities
Derivative liabilities	6,034
Fair Value, Measurements, Recurring \| Level 2
Assets
Derivative assets	2,513
Liabilities
Derivative liabilities	33,758
Fair Value, Measurements, Recurring \| Level 2 \| Residential Loans at Fair Value
Assets
Loans at fair value	259,675
Fair Value, Measurements, Recurring \| Level 3
Assets
Trading securities	173,281
Available-for-sale securities	1,671,786
MSRs	71,225
Derivative assets	1,707
Liabilities
Derivative liabilities	45
Commercial secured borrowings	66,692
Fair Value, Measurements, Recurring \| Level 3 \| Residential Loans at Fair Value
Assets
Loans at fair value	846,564
Fair Value, Measurements, Recurring \| Level 3 \| Commercial Loans at Fair Value
Assets
Loans at fair value	$ 122,118

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and not elected to be offset.

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The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

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Fair value portion of receivables, including, but not limited to, trade account receivables, note receivables, and loan receivables.

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Fair value of an asset representing net future revenue from contractually specified servicing fees, late charges, and other ancillary revenues, in excess of future costs related to servicing arrangements.

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Amount of investments in debt and equity securities and other forms of securities that provide ownership interests classified as trading.

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