Investment Securities (Schedule Of Realized Gross Gains And Losses On Sale From Available For Sale Portfolio) (Details) - USD ($)		3 Months Ended
		Mar. 31, 2016		Mar. 31, 2015		Dec. 31, 2015
Schedule of Investments [Line Items]
Gross gains on sales of securities		$ 3,837,000		$ 276,000
Gross (losses) on sales of securities		(2,263,000)		0
Net gain/(loss) on sales of securities	[1]	1,574,000		276,000
Proceeds from sales		1,000,000		300,000
Debt securities gains/(losses), net		1,700,000
Available For Sale Securities		4,014,405,000	[2]	$ 3,672,331,000	[3]	$ 3,929,846,000
Swap [Member]
Schedule of Investments [Line Items]
Available For Sale Securities		$ 294,000,000

[1] Cash p roceeds for the three months ended March 31, 2016 and 2015 were $ 1.0 million and $ . 3 m illion, respectively. 2016 includes a $ 1.7 million gain from an exchange of approximately $ 294 million of AFS debt securities.

[2] Includes $ 3 .1 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 .