Debt - Total Amount of Interest Expense and Discount Accretion on PEAKS Senior Debt (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Debt Instrument [Line Items]
Interest expense	$ 9,991	$ 6,263	$ 20,379	$ 13,164
PEAKS Senior Debt [Member]
Debt Instrument [Line Items]
Interest expense	2,826	5,508	6,085	11,614
Discount accretion	$ 1,365	$ 1,441	$ 3,020	$ 2,982