Investments (Gross Unrealized Losses And Fair Value Of Investments) (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Less Than Twelve Months
Estimated Fair Value	$ 16,713	$ 9,637
Unrealized Loss	8,768	10,337
Estimated Fair Value	939,870	955,196
Twelve Months or Greater
Unrealized Loss	148,732	133,941
Estimated Fair Value	956,583	964,833
Unrealized Loss	157,500	144,278
Obligations of states and political subdivisions
Less Than Twelve Months
Estimated Fair Value	14,599	7,591
Unrealized Loss	200	66
Estimated Fair Value	181,421	180,560
Twelve Months or Greater
Unrealized Loss	16,927	16,023
Estimated Fair Value	196,020	188,151
Unrealized Loss	17,127	16,089
U.S. Government agencies
Less Than Twelve Months
Estimated Fair Value	265	2,046
Unrealized Loss	8,546	10,271
Estimated Fair Value	724,601	740,911
Twelve Months or Greater
Unrealized Loss	129,560	115,482
Estimated Fair Value	724,866	742,957
Unrealized Loss	138,106	125,753
Private label
Less Than Twelve Months
Estimated Fair Value	1,849	0
Unrealized Loss	22	0
Estimated Fair Value	4,848	4,838
Twelve Months or Greater
Unrealized Loss	262	293
Estimated Fair Value	6,697	4,838
Unrealized Loss	284	293
Trust preferred securities
Less Than Twelve Months
Estimated Fair Value	0	0
Unrealized Loss	0	0
Estimated Fair Value	4,449	4,278
Twelve Months or Greater
Unrealized Loss	151	321
Estimated Fair Value	4,449	4,278
Unrealized Loss	151	321
Corporate securities
Less Than Twelve Months
Estimated Fair Value	0	0
Unrealized Loss	0	0
Estimated Fair Value	24,551	24,609
Twelve Months or Greater
Unrealized Loss	1,832	1,822
Estimated Fair Value	24,551	24,609
Unrealized Loss	$ 1,832	$ 1,822