Private Education Loans - Schedule of Information Regarding Changes in Allowance for Loan Losses (Parenthetical) (Detail) $ in Thousands	3 Months Ended
Mar. 31, 2016 USD ($)
CUSO Student Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recovery of loan losses	$ 221

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration