Variable Interest Entities - Schedule of Revenue and Expenses of PEAKS Trust (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Variable Interest Entity [Line Items]
Student services and administrative expenses	$ 77,899	$ 90,252
Provision for private education loan losses	1,878	1,244
Interest expense	7,099	10,388
Income (loss) before provision for income taxes	7,189	17,265
PEAKS Trust [Member]
Variable Interest Entity [Line Items]
Revenue	2,002	2,413
Student services and administrative expenses	495	541
Provision for private education loan losses	1,483	803
Interest expense	1,758	3,259
Income (loss) before provision for income taxes	$ (1,734)	$ (2,190)