Variable Interest Entities - Schedule of Revenue and Expenses of CUSO (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Variable Interest Entity [Line Items]
Student services and administrative expenses	$ 90,252	$ 99,238
Provision for private education loan losses	1,244	0
Interest expense	10,388	11,812
Income (loss) before provision for income taxes	17,265	$ 1,230
CUSO [Member]
Variable Interest Entity [Line Items]
Revenue	1,064
Student services and administrative expenses	396
Provision for private education loan losses	441
Interest expense	3,641
Income (loss) before provision for income taxes	$ (3,414)