Investment Securities (Schedule Of Unrealized Loss On Investments) (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	$ 225,845	$ 271,472
Less than 12 Months, Unrealized Losses	745	824
12 Months or Longer, Fair Value	691,208	942,667
12 Months or Longer, Unrealized Losses	6,864	11,531
Total Fair Value, Fair Value	917,053	1,214,139
Total Fair Value, Unrealized Losses	7,609	12,355
Mortgage-Backed Securities Issued By U.S. Government Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	0	0
Less than 12 Months, Unrealized Losses	0	0
12 Months or Longer, Fair Value	18,912	21,488
12 Months or Longer, Unrealized Losses	388	440
Total Fair Value, Fair Value	18,912	21,488
Total Fair Value, Unrealized Losses	388	440
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	225,845	251,134
Less than 12 Months, Unrealized Losses	745	763
12 Months or Longer, Fair Value	591,427	798,282
12 Months or Longer, Unrealized Losses	5,019	8,368
Total Fair Value, Fair Value	817,272	1,049,416
Total Fair Value, Unrealized Losses	5,764	9,131
Collateralized Mortgage Obligations Issued By U.S. Government Sponsored Enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	0	20,338
Less than 12 Months, Unrealized Losses	0	61
12 Months or Longer, Fair Value	76,198	119,172
12 Months or Longer, Unrealized Losses	917	2,281
Total Fair Value, Fair Value	76,198	139,510
Total Fair Value, Unrealized Losses	917	2,342
State And Municipal Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	0	0
Less than 12 Months, Unrealized Losses	0	0
12 Months or Longer, Fair Value	48	45
12 Months or Longer, Unrealized Losses	1	1
Total Fair Value, Fair Value	48	45
Total Fair Value, Unrealized Losses	1	1
Other Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	0	0
Less than 12 Months, Unrealized Losses	0	0
12 Months or Longer, Fair Value	4,623	3,680
12 Months or Longer, Unrealized Losses	539	441
Total Fair Value, Fair Value	4,623	3,680
Total Fair Value, Unrealized Losses	$ 539	$ 441