Investment Securities (Schedule Of Maturities Of Investment Securities) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Investment Holdings [Line Items]
Available-for-sale Securities, Three months or less, Amortized Cost	$ 4,648
Available-for-sale Securities, Over three months through twelve months, Amortized Cost	72,886
Available-for-sale Securities, After one year through five years, Amortized Cost	1,646,982
Available-for-sale Securities, After five years through ten years, Amortized Cost	602,427
Available-for-sale Securities, After ten years, Amortized Cost	197,797
Available-for-sale Securities, Amortized Cost	2,526,699
Available-for-sale Securities, Three months or less, Fair Value	4,673
Available-for-sale Securities, Over three months through twelve months, Fair Value	73,615
Available-for-sale Securities, After one year through five years, Fair Value	1,648,510
Available-for-sale Securities, After five years through ten years, Fair Value	595,462
Available-for-sale Securities, After ten years, Fair Value	198,277
Available-for-sale Securities, Fair Value	2,522,539
Held-to-maturity Securities, Three months or less, Amortized Cost	0
Held-to-maturity Securities, Over three months through twelve months, Amortized Cost	6
Held-to-maturity Securities, After one year through five years, Amortized Cost	257
Held-to-maturity Securities, After five years through ten years, Amortized Cost	332
Held-to-maturity Securities, After ten years, Amortized Cost	4,014
Held to maturity, at amortized cost	4,609	$ 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	8
Held-to-maturity Securities, After one year through five years, Fair Value	760
Held-to-maturity Securities, After five years through ten years, Fair Value	808
Held-to-maturity Securities, After ten years, Fair Value	4,014
Held-to-maturity Securities, Fair Value	5,590	$ 5,554
Other Investment Securities [Member]
Investment Holdings [Line Items]
Available-for-sale Securities, Amortized Cost	1,959
Available-for-sale Securities, Fair Value	2,002
Held to maturity, at amortized cost	0
Held-to-maturity Securities, Fair Value	$ 0