Investment Securities (Schedule of Credit-Related Impairment Losses on Securities) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Investment Securities [Abstract]
Beginning Balance	$ 3,925	$ 3,883
Additional credit-related impairment loss on securities for which an other-than-temporary impairment was previously recognized	34	42	372
Ending Balance	$ 3,959	$ 3,925	$ 3,883