Variable Interest Entities - Schedule of Payments Made to Entity Related to Guarantee Obligations (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Variable Interest Entity [Line Items]
Recoveries from Charged-Off Loans	$ 0	$ (50)	$ (103)	$ (87)
2009 RSA [Member]
Variable Interest Entity [Line Items]
Regular Payments	77	439	383	668
Discharge Payments	0	0	0	0
Recoveries from Charged-Off Loans	0	(50)	(103)	(87)
Net guarantee obligation payments	$ 77	$ 389	$ 280	$ 581