Available-For-Sale And Held-To-Maturity Securities (Schedule Of Gross Unrealized Losses And The Estimated Fair Value By Length Of Time In A Loss Position) (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2016 USD ($)
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Available-for-sale Securities, Gross unrealized losses, Less than 12 months	$ (4,886)
Available-for-sale Securities, Estimated fair value, Less than 12 months	727,943
Available-for-sale Securities, Gross unrealized losses, 12 months or more	(2,150)
Available-for-sale Securities, Estimated fair value, 12 months or more	82,600
Available-for-sale Securities, Gross unrealized losses, Total	(7,036)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value, Total	810,543
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss	(457)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	242,189
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Loss	(1,266)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	64,002
Held-to-maturity Securities, Continuous Unrealized Loss Position, Aggregate Loss, Total	(1,723)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value, Total	306,191
U.S. Government Agency Securities [Member]
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Available-for-sale Securities, Gross unrealized losses, Less than 12 months	(2)
Available-for-sale Securities, Estimated fair value, Less than 12 months	1,808
Available-for-sale Securities, Gross unrealized losses, Total	(2)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value, Total	1,808
State And Municipal Securities [Member]
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Available-for-sale Securities, Gross unrealized losses, Less than 12 months	(33)
Available-for-sale Securities, Estimated fair value, Less than 12 months	9,467
Available-for-sale Securities, Gross unrealized losses, 12 months or more	(1,859)
Available-for-sale Securities, Estimated fair value, 12 months or more	61,659
Available-for-sale Securities, Gross unrealized losses, Total	(1,892)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value, Total	71,126
Corporate Fixed Income Securities [Member]
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Available-for-sale Securities, Gross unrealized losses, Less than 12 months	(320)
Available-for-sale Securities, Estimated fair value, Less than 12 months	175,119
Available-for-sale Securities, Gross unrealized losses, Total	(320)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value, Total	175,119
Asset-Backed Securities [Member]
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Available-for-sale Securities, Gross unrealized losses, Less than 12 months	(2,233)
Available-for-sale Securities, Estimated fair value, Less than 12 months	241,700
Available-for-sale Securities, Gross unrealized losses, 12 months or more	(83)
Available-for-sale Securities, Estimated fair value, 12 months or more	11,375
Available-for-sale Securities, Gross unrealized losses, Total	(2,316)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value, Total	253,075
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss	(80)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	49,920
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Loss	(1,232)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	61,718
Held-to-maturity Securities, Continuous Unrealized Loss Position, Aggregate Loss, Total	(1,312)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value, Total	111,638
Mortgage Backed Securities [Member] | Agency [Member]
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Available-for-sale Securities, Gross unrealized losses, Less than 12 months	(1,739)
Available-for-sale Securities, Estimated fair value, Less than 12 months	224,447
Available-for-sale Securities, Gross unrealized losses, 12 months or more	(55)
Available-for-sale Securities, Estimated fair value, 12 months or more	7,550
Available-for-sale Securities, Gross unrealized losses, Total	(1,794)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value, Total	231,997
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss	(377)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	192,269
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Loss	(21)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	1,595
Held-to-maturity Securities, Continuous Unrealized Loss Position, Aggregate Loss, Total	(398)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value, Total	193,864
Mortgage Backed Securities [Member] | Commercial [Member]
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Available-for-sale Securities, Gross unrealized losses, Less than 12 months	(559)
Available-for-sale Securities, Estimated fair value, Less than 12 months	75,379
Available-for-sale Securities, Gross unrealized losses, Total	(559)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value, Total	75,379
Mortgage Backed Securities [Member] | Non-Agency [Member]
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Available-for-sale Securities, Estimated fair value, Less than 12 months	23
Available-for-sale Securities, Gross unrealized losses, 12 months or more	(153)
Available-for-sale Securities, Estimated fair value, 12 months or more	2,016
Available-for-sale Securities, Gross unrealized losses, Total	(153)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value, Total	2,039
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Loss	(13)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	689
Held-to-maturity Securities, Continuous Unrealized Loss Position, Aggregate Loss, Total	(13)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value, Total	$ 689