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) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Gross unrealized losses, Less than 12 months	$ (4,836)
Available-for-sale Securities, Estimated fair value, Less than 12 months	473,540
Available-for-sale Securities, Gross unrealized losses, 12 months or more	(9,336)
Available-for-sale Securities, Estimated fair value, 12 months or more	408,234
Available-for-sale Securities, Gross unrealized losses, Total	(14,172)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value, Total	881,774
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss	(91)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	1,051,835
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Loss	13,389
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	8,217
Held-to-maturity Securities, Continuous Unrealized Loss Position, Aggregate Loss, Total	13,480
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value, Total	1,060,052
U.S. Government Agency Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Gross unrealized losses, Less than 12 months	(4)
Available-for-sale Securities, Estimated fair value, Less than 12 months	987
Available-for-sale Securities, Gross unrealized losses, Total	(4)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value, Total	987
State And Municipal Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Gross unrealized losses, Less than 12 months	(6)
Available-for-sale Securities, Estimated fair value, Less than 12 months	2,957
Available-for-sale Securities, Gross unrealized losses, 12 months or more	(2,131)
Available-for-sale Securities, Estimated fair value, 12 months or more	65,294
Available-for-sale Securities, Gross unrealized losses, Total	(2,137)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value, Total	68,251
Mortgage-backed Securities: Agency [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Gross unrealized losses, Less than 12 months	(238)
Available-for-sale Securities, Estimated fair value, Less than 12 months	38,453
Available-for-sale Securities, Gross unrealized losses, 12 months or more	(675)
Available-for-sale Securities, Estimated fair value, 12 months or more	46,533
Available-for-sale Securities, Gross unrealized losses, Total	(913)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value, Total	84,986
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss	(91)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	846,119
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Loss	7,824
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	8,217
Held-to-maturity Securities, Continuous Unrealized Loss Position, Aggregate Loss, Total	7,915
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value, Total	854,336
Commercial [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Gross unrealized losses, Less than 12 months	(7)
Available-for-sale Securities, Estimated fair value, Less than 12 months	4,893
Available-for-sale Securities, Gross unrealized losses, 12 months or more	(82)
Available-for-sale Securities, Estimated fair value, 12 months or more	10,043
Available-for-sale Securities, Gross unrealized losses, Total	(89)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value, Total	14,936
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	59,804
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Loss	186
Held-to-maturity Securities, Continuous Unrealized Loss Position, Aggregate Loss, Total	186
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value, Total	59,804
Corporate Fixed Income Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Gross unrealized losses, Less than 12 months	(80)
Available-for-sale Securities, Estimated fair value, Less than 12 months	33,940
Available-for-sale Securities, Gross unrealized losses, 12 months or more	(740)
Available-for-sale Securities, Estimated fair value, 12 months or more	65,003
Available-for-sale Securities, Gross unrealized losses, Total	(820)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value, Total	98,943
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	50,332
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Loss	2,605
Held-to-maturity Securities, Continuous Unrealized Loss Position, Aggregate Loss, Total	2,605
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value, Total	50,332
Asset-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Gross unrealized losses, Less than 12 months	(4,447)
Available-for-sale Securities, Estimated fair value, Less than 12 months	389,422
Available-for-sale Securities, Gross unrealized losses, 12 months or more	(5,708)
Available-for-sale Securities, Estimated fair value, 12 months or more	221,361
Available-for-sale Securities, Gross unrealized losses, Total	(10,155)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value, Total	610,783
Held-to-maturity Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value	95,580
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Aggregate Loss	2,774
Held-to-maturity Securities, Continuous Unrealized Loss Position, Aggregate Loss, Total	2,774
Held-to-maturity Securities, Continuous Unrealized Loss Position, Fair Value, Total	$ 95,580