Derivative Activities (Netting Of Derivative Contracts) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Derivative Activities [Abstract]
Asset derivatives, gross	$ 98,500	$ 122,143
Asset derivatives, netting	(10,613)	(11,594)
Asset derivatives, net	87,887	110,549
Liability derivatives, gross	26,366	25,720
Liability derivatives, netting	(10,613)	(11,594)
Liability derivatives, net	$ 15,753	$ 14,126