Investment Securities (Proceeds From Sales Of Securities And Components Of Investment Securities Gains And Losses) (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015		Sep. 30, 2014
Investment [Line Items]
Proceeds from sales of available for sale securities				$ 675,870		$ 30,998
Proceeds from sales of non-marketable securities				9,023		33,043
Total proceeds	[1]			684,893		64,041
Investment securities gains (losses), net		$ (378)	$ 2,995	7,800	[1]	10,474	[1]
Available-for-sale Securities [Member]
Investment [Line Items]
Available-for-sale Securities, gross realized gains on sales				2,813		0
Available-for-sale Securities, gross realized loss on sales				0		(5,197)
Gain realized on donation				0		1,570
Other-than-temporary impairment recognized on debt securities				(483)		(1,348)
Non-Marketable [Member]
Investment [Line Items]
Gains realized on sales				2,516		1,613
Losses realized on sales				0		(134)
Fair value adjustments, net				$ 2,954		$ 13,970

[1] Available for sale and non-marketable securities