Investments (Gross Unrealized Losses And Fair Value Of Investments) (Details) - USD ($) $ in Thousands	Mar. 31, 2025	Dec. 31, 2024
Less Than Twelve Months
Estimated Fair Value	$ 26,113	$ 134,284
Unrealized Loss	9,051	13,091
Estimated Fair Value	894,102	891,127
Twelve Months or Greater
Unrealized Loss	123,635	138,469
Estimated Fair Value	920,215	1,025,411
Unrealized Loss	132,686	151,560
Obligations of states and political subdivisions
Less Than Twelve Months
Estimated Fair Value	14,988	19,724
Unrealized Loss	221	422
Estimated Fair Value	152,140	151,508
Twelve Months or Greater
Unrealized Loss	15,348	15,097
Estimated Fair Value	167,128	171,232
Unrealized Loss	15,569	15,519
U.S. Government agencies
Less Than Twelve Months
Estimated Fair Value	11,125	114,560
Unrealized Loss	8,830	12,669
Estimated Fair Value	712,795	710,651
Twelve Months or Greater
Unrealized Loss	107,177	121,998
Estimated Fair Value	723,920	825,211
Unrealized Loss	116,007	134,667
Private label
Less Than Twelve Months
Estimated Fair Value	0	0
Unrealized Loss	0	0
Estimated Fair Value	4,947	4,933
Twelve Months or Greater
Unrealized Loss	134	163
Estimated Fair Value	4,947	4,933
Unrealized Loss	134	163
Trust preferred securities
Less Than Twelve Months
Estimated Fair Value	0	0
Unrealized Loss	0	0
Estimated Fair Value	0	0
Twelve Months or Greater
Unrealized Loss	0	0
Estimated Fair Value	0	0
Unrealized Loss	0	0
Corporate securities
Less Than Twelve Months
Estimated Fair Value	0	0
Unrealized Loss	0	0
Estimated Fair Value	24,220	24,035
Twelve Months or Greater
Unrealized Loss	976	1,211
Estimated Fair Value	24,220	24,035
Unrealized Loss	$ 976	$ 1,211