Investments (Gross Unrealized Losses And Fair Value Of Investments) (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 9,637	$ 766,882
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	10,337	75,309
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	955,196	394,860
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	133,941	93,680
Debt Securities, Available-for-sale, Unrealized Loss Position	964,833	1,161,742
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	144,278	168,989
Debt Securities, Available-for-Sale, Allowance for Credit Loss	0	0
Obligations of states and political subdivisions
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	7,591	203,173
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	66	21,929
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	180,560	13,359
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	16,023	2,395
Debt Securities, Available-for-sale, Unrealized Loss Position	188,151	216,532
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	16,089	24,324
U.S. Government agencies
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	2,046	533,611
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	10,271	50,268
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	741,011	376,778
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	115,482	90,418
Debt Securities, Available-for-sale, Unrealized Loss Position	743,057	910,389
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	125,753	140,686
Private label
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	0	7,126
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	464
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	4,738	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	293	0
Debt Securities, Available-for-sale, Unrealized Loss Position	4,738	7,126
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	293	464
Trust preferred securities
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	0	0
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	4,278	3,828
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	321	762
Debt Securities, Available-for-sale, Unrealized Loss Position	4,278	3,828
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	321	762
Corporate securities
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	0	22,972
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	2,648
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	24,609	895
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	1,822	105
Debt Securities, Available-for-sale, Unrealized Loss Position	24,609	23,867
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	$ 1,822	$ 2,753