Private Education Loans - Schedule of Information Regarding Changes in Allowance for Loan Losses (Detail) (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]
Provision for loan losses	$ 4,511	$ 16,382	$ 13,582	$ 20,701
PEAKS Trust Student Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance at beginning of period	38,420	4,319	29,349	0
Loans charged off	0	0	0	0
Recoveries from charged off loans	0	0	0	0
Provision for loan losses	4,511	16,382	13,582	20,701
Balance at end of period	$ 42,931	$ 20,701	$ 42,931	$ 20,701