Investment Securities (Schedule Of Realized Gross Gains And Losses On Sale From Available For Sale Portfolio) (Details) - USD ($) $ in Thousands		3 Months Ended				6 Months Ended
		Jun. 30, 2016		Jun. 30, 2015		Jun. 30, 2016		Jun. 30, 2015		Dec. 31, 2015
Schedule of Investments [Line Items]
Gross gains on sales of securities		$ 162		$ 8		$ 3,999		$ 284
Gross (losses) on sales of securities		(63)		0		(2,326)		0
Net gain/(loss) on sales of securities	[1]	99		8		1,673		284
Proceeds from sales		600				1,500		300
Debt securities gains/(losses), net						1,700
Available For Sale Securities		4,009,243	[2]	$ 3,648,860	[3]	4,009,243	[2]	$ 3,648,860	[3]	$ 3,929,846
Swap [Member]
Schedule of Investments [Line Items]
Available For Sale Securities		$ 294,000				$ 294,000

[1] Cash proceeds for the three months ended June 30, 2016 were $ .6 million; cash proceeds for the three months ended June 30, 2015 were not material. Proceeds for the six months ended June 30, 2016 and 2015, respectively, were $ 1.5 million and $ .3 million. Six months ended June 30, 2016 includes a $ 1.7 million gain from an exchange of approximately $ 294 million of AFS debt securities.

[2] Includes $ 3 . 4 billion of securities pledged to secure public deposits, securities sold under agreements to repurchase, and for other purposes.

[3] Includes $ 3.2 billion of securities pledged to secure public deposits, securities sold under agreements to repu rchase, and for other purposes .