Private Education Loans - Schedule of Estimated Fair Value, Accretable Yield and Expected Cash Flows (Detail) - USD ($) $ in Thousands	Sep. 30, 2014	Feb. 28, 2013
PEAKS Trust Student Loans [Member]
Acquired Impaired Loans Rollforward [Line Items]
Estimated fair value		$ 112,116
Accretable yield		100,953
Expected cash flows		213,069
PEAKS Trust Student Loans [Member] | Analogy [Member]
Acquired Impaired Loans Rollforward [Line Items]
Estimated fair value		60,177
Accretable yield		58,843
Expected cash flows		$ 119,020
CUSO Student Loans [Member]
Acquired Impaired Loans Rollforward [Line Items]
Estimated fair value	$ 27,199
Accretable yield	12,498
Expected cash flows	39,697
CUSO Student Loans [Member] | Analogy [Member]
Acquired Impaired Loans Rollforward [Line Items]
Estimated fair value	12,799
Accretable yield	5,651
Expected cash flows	$ 18,450