Commitments and Contingencies - Aggregate Amount of Guarantee Payments, Discharge Payments and Payments on Behalf of Borrowers (Detail) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Schedule of Claims and Contingencies [Line Items]
PEAKS Guarantee			$ 159,300
Payments on Behalf of Borrowers			$ 1,832
Total	$ 18,626	$ 43,703
CUSO RSA [Member]
Schedule of Claims and Contingencies [Line Items]
Regular Payments	2,280	1,158
Discharge Payments	2,709	0
PEAKS Program [Member]
Schedule of Claims and Contingencies [Line Items]
PEAKS Guarantee	13,637	40,713
Payments on Behalf of Borrowers	$ 0	$ 1,832