Private Education Loans - Schedule of Contractually Required Future Principal and Interest Payments, Expected Cash Flows and Nonaccretable Difference (Detail) - USD ($) $ in Thousands	Sep. 30, 2014	Feb. 28, 2013
PEAKS Trust Student Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Contractual future principal and interest payments		$ 487,800
Expected cash flows		213,069
Nonaccretable difference		274,731
PEAKS Trust Student Loans [Member] | Analogy [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Contractual future principal and interest payments		213,600
Expected cash flows		119,020
Nonaccretable difference		$ 94,580
CUSO Student Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Contractual future principal and interest payments	$ 111,159
Expected cash flows	39,697
Nonaccretable difference	71,462
CUSO Student Loans [Member] | Analogy [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Contractual future principal and interest payments	36,715
Expected cash flows	18,450
Nonaccretable difference	$ 18,265