Private Education Loans - Schedule of Information Regarding Aggregate Changes in Accretable Yield (Detail) (PEAKS Trust Student Loans [Member], USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended
Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance at beginning of period	$ 59,929	$ 99,475	$ 70,580	$ 0
Additions resulting from the PEAKS Consolidation			0	100,953
Accretion	(2,727)	(4,072)	(9,099)	(9,536)
Reclassification from nonaccretable difference and changes in expected cash flows	(2,077)	(16,513)	(6,356)	(12,527)
Balance at end of period	55,125	78,890	55,125	78,890
Analogy [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance at beginning of period	36,444	60,533	42,274	0
Additions resulting from the PEAKS Consolidation			0	58,843
Accretion	(1,602)	(2,334)	(5,302)	(5,282)
Reclassification from nonaccretable difference and changes in expected cash flows	(830)	(11,451)	(2,960)	(6,813)
Balance at end of period	$ 34,012	$ 46,748	$ 34,012	$ 46,748

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Amount of the excess of a loan's cash flows expected to be collected over the investor's initial investment in acquired loans not accounted for as debt securities with evidence of deterioration of credit quality.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 30

-Section 15

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=27045933&loc=d3e13503-111538

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 30

-Section 50

-Paragraph 2

-Subparagraph (a)(2)

-URI http://asc.fasb.org/extlink&oid=6379141&loc=d3e15032-111544

+ Details

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- Definition

Amount of decrease from accretion of the excess of a loan's cash flows expected to be collected over the investor's initial investment in acquired loans not accounted for as debt securities with evidence of deterioration of credit quality.

+ References

+ Details

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- Definition

Amount of additions to the excess of a loan's cash flows expected to be collected over the investor's initial investment in acquired loans not accounted for as debt securities with evidence of deterioration of credit quality.

+ References

+ Details

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- Definition

Amount of reclassification (to) from nonaccretable difference (from) to the excess of a loan's cash flows expected to be collected over the investor's initial investment in acquired loans not accounted for as debt securities with evidence of deterioration of credit quality.

+ References

+ Details

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