Variable Interest Entities - Schedule of Carrying Value of Assets and Liabilities Eliminated from Financial Statement (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Feb. 28, 2013
Variable Interest Entity [Line Items]
Total assets	$ (664,014)	$ (752,838)
Other current liabilities	(31,973)	(27,153)
Total liabilities	(502,878)	(610,766)
PEAKS Trust [Member]
Variable Interest Entity [Line Items]
Total assets	(53,195)	(68,627)	$ (113,819)
Other current liabilities	(191)	(199)	(471)
Total liabilities	$ (50,997)	$ (85,910)	(226,567)
PEAKS Trust [Member] | Consolidation, Eliminations [Member]
Variable Interest Entity [Line Items]
Other assets			6,614
Total assets			6,614
Other current liabilities			3,060
Other liabilities			43,054
Total liabilities			$ 46,114