Private Education Loans - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2015 USD ($) Pool_Loan	Feb. 28, 2013 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, outstanding amount	$ 161,436,000
Allowance for loan losses		$ 0
Private Education Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, carrying amount	$ 86,069,000
PEAKS Trust Student Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of separate pools of loans | Pool_Loan	24
CUSO Student Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of separate pools of loans | Pool_Loan	48