Commitments and Contingencies - Aggregate Amount of Guarantee Payments, Discharge Payments and Payments on Behalf of Borrowers (Parenthetical) (Detail) (USD $) In Thousands, unless otherwise specified	1 Months Ended	9 Months Ended	3 Months Ended	9 Months Ended
	Feb. 28, 2013	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2014
PEAKS Program [Member]
Schedule of Claims and Contingencies [Line Items]
Guarantee payments paid to prior consolidation	$ 854	$ 854
Payments on behalf of borrowers prior to consolidation	532	532
2009 RSA [Member]
Schedule of Claims and Contingencies [Line Items]
Recoveries from charged-off loans owed related to regular payments obligation			$ 156	$ 156