Variable Interest Entities - Guarantee and Other Payments Related to PEAKS Program (Detail) (USD $) In Thousands, unless otherwise specified	1 Months Ended	2 Months Ended	3 Months Ended
	Mar. 31, 2013	Feb. 28, 2013	Mar. 31, 2013	Mar. 31, 2012
Variable Interest Entity [Line Items]
Payments on Behalf of Borrowers			$ 1,855	$ 0
PEAKS Program [Member]
Variable Interest Entity [Line Items]
PEAKS Guarantee	385	854	1,239	0
Payments on Behalf of Borrowers	1,323	532	1,855	0
Total	$ 1,708	$ 1,386	$ 3,094	$ 0