Investment Securities (Proceeds From Sales Of Securities And Components Of Investment Securities Gains And Losses) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Investment [Line Items]
Proceeds from Sale of Available-for-sale Securities	$ 667,227	$ 779,793	$ 2,047
Proceeds from sale of equity securities	41,637	10,953	3,026
Proceeds from sales of non-marketable securities	0	1,634	19,307
Total proceeds	708,864	792,380	24,380
Investment securities gains (losses), net	(488)	25,051	(53)
Available-for-sale Securities [Member]
Investment [Line Items]
Loss Realized on Called Bond	0	(254)	0
Gains realized on sales	448	592	109
Loss realized on sales	(10,101)	(10,287)	0
Other-than-temporary impairment recognized on debt securities	(68)	(385)	(270)
Equity securities [Member]
Investment [Line Items]
Gain realized on donation	0	31,074	0
Equity Securities, FV-NI, Realized Gain	1,759	10,653	1,911
Equity Securities, FV-NI, Realized Loss	(8,917)	(10)	(7)
Equity Securities, Fair value adjustments, net	2,542	0	0
Other Investments [Member]
Investment [Line Items]
Gains realized on sales	0	381	2,442
Other securities, loss realized on sales	0	(880)	(499)
Fair value adjustments, net	$ 13,849	$ (5,833)	$ (3,739)