Variable Interest Entities - Additional Information (Detail)		1 Months Ended	3 Months Ended			6 Months Ended		9 Months Ended	12 Months Ended
	Mar. 20, 2014 USD ($)	Jan. 31, 2014 USD ($)	Jun. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Jun. 30, 2014 USD ($)	Jun. 30, 2015 USD ($) Installment	Jun. 30, 2014 USD ($)	Sep. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Variable Interest Entity [Line Items]
Payments on Behalf of Borrowers									$ 1,832,000
Prepayment of Senior debt									159,300,000
Offset amounts under Revolving Note			$ 0		$ 0	$ 0	$ 0
PEAKS Trust [Member]
Variable Interest Entity [Line Items]
Payments on Behalf of Borrowers		$ 1,832,000
PEAKS Trust [Member] | 2014 Payment [Member]
Variable Interest Entity [Line Items]
Prepayment of Senior debt	$ 40,000,000
CUSO [Member]
Variable Interest Entity [Line Items]
Number of monthly payments | Installment						10
Discount rate						10.00%
Gain (loss) on consolidation				$ 16,631,000				$ 16,631,000
Revenue or expenses on consolidation of income					0		0
Recoveries from charged-off loans			0		256,000	$ 0	475,000		475,000
Offset amounts under Revolving Note										$ 8,472,000
Revolving note, amount owned to company			$ 8,200,000		$ 8,200,000	$ 8,200,000	$ 8,200,000		$ 8,200,000
CUSO [Member] | Fair Value [Member]
Variable Interest Entity [Line Items]
Amount of liabilities exceeded assets				94,970,000				94,970,000
CUSO [Member] | Carrying Value [Member]
Variable Interest Entity [Line Items]
Amount of liabilities exceeded assets				$ 111,601,000				$ 111,601,000