Contingencies - Aggregate Amount of Guarantee Payments and Payments on Behalf of Borrowers (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Risk Share Agreement [Member]
Schedule of Claims and Contingencies [Line Items]
Payments on Behalf of Borrowers	$ 2,502	$ 0	$ 7,647	$ 0
Total	3,098	803	9,762	1,643
PEAKS Guarantee [Member]
Schedule of Claims and Contingencies [Line Items]
Guarantee	138	243	1,377	502
Payments on Behalf of Borrowers	2,502	0	7,647	0
PEAKS Guarantee [Member] | Risk Share Agreement [Member]
Schedule of Claims and Contingencies [Line Items]
Guarantee	138	243	1,377	502
2009 RSA [Member]
Schedule of Claims and Contingencies [Line Items]
Guarantee	458	560	738	1,141
2009 RSA [Member] | Risk Share Agreement [Member]
Schedule of Claims and Contingencies [Line Items]
Guarantee	$ 458	$ 560	$ 738	$ 1,141