Investments (Gross Unrealized Losses And Fair Value Of Investments) (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Less Than Twelve Months
Estimated Fair Value	$ 160,056	$ 766,882
Unrealized Loss	18,722	75,309
Estimated Fair Value	940,646	394,860
Twelve Months or Greater
Unrealized Loss	148,589	93,680
Estimated Fair Value	1,100,702	1,161,742
Unrealized Loss	167,311	168,989
Obligations of states and political subdivisions
Less Than Twelve Months
Estimated Fair Value	43,264	203,173
Unrealized Loss	1,102	21,929
Estimated Fair Value	169,087	13,359
Twelve Months or Greater
Unrealized Loss	19,379	2,395
Estimated Fair Value	212,351	216,532
Unrealized Loss	20,481	24,324
U.S. Government agencies
Less Than Twelve Months
Estimated Fair Value	105,588	533,611
Unrealized Loss	16,261	50,268
Estimated Fair Value	746,989	376,778
Twelve Months or Greater
Unrealized Loss	126,475	90,418
Estimated Fair Value	852,577	910,389
Unrealized Loss	142,736	140,686
Trust preferred securities
Less Than Twelve Months
Estimated Fair Value	0	0
Unrealized Loss	0	0
Estimated Fair Value	4,192	3,828
Twelve Months or Greater
Unrealized Loss	403	762
Estimated Fair Value	4,192	3,828
Unrealized Loss	403	762
Corporate securities
Less Than Twelve Months
Estimated Fair Value	11,204	22,972
Unrealized Loss	1,359	2,648
Estimated Fair Value	13,688	895
Twelve Months or Greater
Unrealized Loss	1,834	105
Estimated Fair Value	24,892	23,867
Unrealized Loss	3,193	2,753
Private label
Less Than Twelve Months
Estimated Fair Value	0	7,126
Unrealized Loss	0	464
Estimated Fair Value	6,690	0
Twelve Months or Greater
Unrealized Loss	498	0
Estimated Fair Value	6,690	7,126
Unrealized Loss	$ 498	$ 464