Investment Securities (Securities With Unrealized Losses And Length Of Impairment Period) (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 318,063	$ 1,136,297
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	4,678	9,413
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	236,270	517,817
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	8,383	3,451
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	554,333	1,654,114
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	13,061	12,864
U.S. Government and Federal Agency Obligations [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	0	31,787
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	21
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	0	25,405
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	21
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	0	57,192
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	0	42
Government-Sponsored Enterprise Obligations [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	19,586	6,155
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	232	187
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	0	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	0
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	19,586	6,155
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	232	187
State and Municipal Obligations [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	20,798	6,700
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	234	31
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	0	1,554
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	1
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	20,798	8,254
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	234	32
Agency Mortgage-Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	66,232	652,352
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	149	5,306
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	12	147,653
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	867
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	66,244	800,005
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	149	6,173
Non-Agency Mortgage-Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	14,892	102,931
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	14	254
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	10,128	189,747
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	60	451
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	25,020	292,678
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	74	705
Asset-Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	196,555	330,876
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	4,049	3,610
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	226,130	152,461
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	8,323	2,108
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	422,685	483,337
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	12,372	5,718
Total Mortgage And Asset-Backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	277,679	1,086,159
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	4,212	9,170
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	236,270	489,861
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	8,383	3,426
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	513,949	1,576,020
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	12,595	12,596
Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	0	5,496
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	4
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	0	997
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	3
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	0	6,493
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss, Total	$ 0	$ 7

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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