Investment Securities (Schedule Of Maturities Of Investment Securities) (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Investment Holdings [Line Items]
Available-for-sale Securities, Three months or less, Amortized Cost	$ 13,055
Available-for-sale Securities, Over three months through twelve months, Amortized Cost	82,603
Available-for-sale Securities, After one year through five years, Amortized Cost	1,778,642
Available-for-sale Securities, After five years through ten years, Amortized Cost	431,360
Available-for-sale Securities, After ten years, Amortized Cost	151,920
Available-for-sale Securities, Amortized Cost	2,459,596
Available-for-sale Securities, Three months or less, Fair Value	13,108
Available-for-sale Securities, Over three months through twelve months, Fair Value	83,377
Available-for-sale Securities, After one year through five years, Fair Value	1,798,598
Available-for-sale Securities, After five years through ten years, Fair Value	431,514
Available-for-sale Securities, After ten years, Fair Value	153,800
Available-for-sale Securities, Fair Value	2,482,478
Held-to-maturity Securities, Three months or less, Amortized Cost	0
Held-to-maturity Securities, Over three months through twelve months, Amortized Cost	9
Held-to-maturity Securities, After one year through five years, Amortized Cost	391
Held-to-maturity Securities, After five years through ten years, Amortized Cost	239
Held-to-maturity Securities, After ten years, Amortized Cost	4,060
Investment securities held to maturity	4,699	$ 5,211
Held-to-maturity Securities, Three months or less, Fair Value	0
Held-to-maturity Securities, Over three months through twelve months, Fair Value	12
Held-to-maturity Securities, After one year through five years, Fair Value	934
Held-to-maturity Securities, After five years through ten years, Fair Value	273
Held-to-maturity Securities, After ten years, Fair Value	4,061
Held-to-maturity Securities, Fair Value	5,280	$ 5,554
Other Investment Securities [Member]
Investment Holdings [Line Items]
Available-for-sale Securities, Amortized Cost	2,016
Available-for-sale Securities, Fair Value	2,081
Investment securities held to maturity	0
Held-to-maturity Securities, Fair Value	$ 0