Variable Interest Entities - Guarantee and Other Payments Related to PEAKS Program (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended		2 Months Ended	3 Months Ended	4 Months Ended	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Feb. 28, 2013 PEAKS Program [Member]	Jun. 30, 2013 PEAKS Program [Member]	Jun. 30, 2013 PEAKS Program [Member]	Jun. 30, 2012 PEAKS Program [Member]
Variable Interest Entity [Line Items]
PEAKS Guarantee					$ 854	$ 1,239	$ 385	$ 258
Payments on Behalf of Borrowers	3,290	0	5,145	0	532	5,145	4,613	0
Total					$ 1,386	$ 6,384	$ 4,998	$ 258