Commitments and Contingencies - Aggregate Amount of Guarantee Payments (Detail) - USD ($) $ in Thousands	3 Months Ended				12 Months Ended
	Mar. 31, 2016		Mar. 31, 2015		Dec. 31, 2015
Schedule of Claims and Contingencies [Line Items]
PEAKS Guarantee Payment					$ 30,090
Total	$ 12,462		$ 18,626
PEAKS Program [Member]
Schedule of Claims and Contingencies [Line Items]
PEAKS Guarantee Payment	4,534		13,637
CUSO RSA [Member]
Schedule of Claims and Contingencies [Line Items]
CUSO RSA Regular Payments	2,597	[1],[2]	2,280	[3],[4]
CUSO RSA Discharge Payments	0		2,709
CUSO RSA Deferred Payment	$ 5,331	[5]	$ 0

[1] This amount is net of $294 of recoveries from charged-off loans owed to us that we offset against amounts owed by us under the CUSO RSA.

[2] This amount is net of $294 of recoveries from charged-off loans owed to us that we offset against amounts we owed under the CUSO RSA.

[3] This amount is net of $290 of recoveries from charged-off loans owed to us that we offset against amounts owed by us under the CUSO RSA.

[4] This amount is net of $290 of recoveries from charged-off loans owed to us that we offset against amounts we owed under the CUSO RSA.

[5] This amount is net of $761 of recoveries from charged-off loans received by the CUSO from June 8, 2015 through December 31, 2015 that were not paid to us that we offset against amounts owed by us under the CUSO RSA in January 2016.