Commitments and Contingencies - (Reserve For Unfunded Credit Commitments) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Reserve For Unfunded Credit Commitments [Roll Forward]
Beginning balance	$ 5,463	$ 5,816	$ 5,449	$ 9,378
Provision	0		0
Reserve release	(267)	(576)	(253)	(4,138)
Ending balance	$ 5,196	$ 5,240	$ 5,196	$ 5,240