Investments (Gross Unrealized Losses And Fair Value Of Investments) (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Less Than Twelve Months
Estimated Fair Value	$ 5,977	$ 9,637
Unrealized Loss	45	10,337
Estimated Fair Value	978,774	955,196
Twelve Months or Greater
Unrealized Loss	116,043	133,941
Estimated Fair Value	984,751	964,833
Unrealized Loss	116,088	144,278
Obligations of states and political subdivisions
Less Than Twelve Months
Estimated Fair Value	4,683	7,591
Unrealized Loss	33	66
Estimated Fair Value	178,275	180,560
Twelve Months or Greater
Unrealized Loss	13,772	16,023
Estimated Fair Value	182,958	188,151
Unrealized Loss	13,805	16,089
U.S. Government agencies
Less Than Twelve Months
Estimated Fair Value	0	2,046
Unrealized Loss	0	10,271
Estimated Fair Value	766,660	740,914
Twelve Months or Greater
Unrealized Loss	101,113	115,482
Estimated Fair Value	766,660	742,960
Unrealized Loss	101,113	125,753
Private label
Less Than Twelve Months
Estimated Fair Value	1,294	0
Unrealized Loss	12	0
Estimated Fair Value	5,002	4,835
Twelve Months or Greater
Unrealized Loss	97	293
Estimated Fair Value	6,296	4,835
Unrealized Loss	109	293
Trust preferred securities
Less Than Twelve Months
Estimated Fair Value	0	0
Unrealized Loss	0	0
Estimated Fair Value	4,515	4,278
Twelve Months or Greater
Unrealized Loss	89	321
Estimated Fair Value	4,515	4,278
Unrealized Loss	89	321
Corporate securities
Less Than Twelve Months
Estimated Fair Value	0	0
Unrealized Loss	0	0
Estimated Fair Value	24,322	24,609
Twelve Months or Greater
Unrealized Loss	972	1,822
Estimated Fair Value	24,322	24,609
Unrealized Loss	$ 972	$ 1,822