Debt - Total Amount of Interest Expense and Discount Accretion on PEAKS Senior Debt (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Debt Instrument [Line Items]
Interest expense	$ 9,709	$ 9,292	$ 30,088	$ 28,315
PEAKS Senior Debt [Member]
Debt Instrument [Line Items]
Interest expense	2,760	8,722	8,845	26,195
Discount accretion	$ 1,455	$ 5,249	$ 4,475	$ 14,090