Investment Securities (Debt Securities for which Credit Loss was Recognized in Income and Other Losses Recorded in Other Comprehensive Income) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Investment Securities [Abstract]
Credit losses on debt securities held, beginning of year	$ 1,205	$ 1,205	$ 3,567
Reductions related to actual losses incurred			(2,362)
Reductions for previous credit losses realized on securities sold during the year	(1,096)
Credit losses on debt securities held, end of period	$ 109	$ 1,205	$ 1,205