Debt - Total Amount of Interest Expense and Discount Accretion on PEAKS Senior Debt (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Debt Instrument [Line Items]
Interest expense	$ 5,831	$ 7,190	$ 18,995	$ 18,133
PEAKS Senior Debt [Member]
Debt Instrument [Line Items]
Interest expense	5,261	6,275	16,875	14,953
Discount accretion	$ 1,788	$ 1,411	$ 4,770	$ 3,444