Private Education Loans - Schedule of Information Regarding Changes in Allowance for Loan Losses (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Provision for loan losses	$ 1,244	$ 0
PEAKS Trust Student Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance at beginning of period	42,353	29,349
Loans charged off	(4,061)	0
Recoveries from charged off loans	501	0
Provision for loan losses	803	0
Balance at end of period	39,596	$ 29,349
CUSO Student Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Balance at beginning of period	2,039
Loans charged off	0
Recoveries from charged off loans	0
Provision for loan losses	441
Balance at end of period	$ 2,480