Variable Interest Entities - Guarantee and Other Payments Related to PEAKS Program (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Variable Interest Entity [Line Items]
Payments on Behalf of Borrowers	$ 1,832	$ 11,499
PEAKS Program [Member]
Variable Interest Entity [Line Items]
PEAKS Guarantee	159,255	2,413
Payments on Behalf of Borrowers	1,832	11,499
Total	$ 161,087	$ 13,912