Investments (Gross Unrealized Losses And Fair Value Of Investments) (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Less Than Twelve Months
Estimated Fair Value	$ 1,077,779	$ 535,672
Unrealized Loss	93,464	4,966
Estimated Fair Value	64,143	29,918
Twelve Months or Greater
Unrealized Loss	13,991	437
Estimated Fair Value	1,141,922	565,590
Unrealized Loss	107,455	5,403
Obligations of states and political subdivisions
Less Than Twelve Months
Estimated Fair Value	184,415	13,277
Unrealized Loss	21,399	152
Estimated Fair Value	3,084	2,420
Twelve Months or Greater
Unrealized Loss	369	63
Estimated Fair Value	187,499	15,697
Unrealized Loss	21,768	215
U.S. Government agencies
Less Than Twelve Months
Estimated Fair Value	871,121	521,407
Unrealized Loss	70,168	4,802
Estimated Fair Value	57,259	23,295
Twelve Months or Greater
Unrealized Loss	12,843	7
Estimated Fair Value	928,380	544,702
Unrealized Loss	83,011	4,809
Trust preferred securities
Less Than Twelve Months
Estimated Fair Value	0	0
Unrealized Loss	0	0
Estimated Fair Value	3,800	4,203
Twelve Months or Greater
Unrealized Loss	779	367
Estimated Fair Value	3,800	4,203
Unrealized Loss	779	367
Corporate securities
Less Than Twelve Months
Estimated Fair Value	14,482	988
Unrealized Loss	1,711	12
Estimated Fair Value	0	0
Twelve Months or Greater
Unrealized Loss	0	0
Estimated Fair Value	14,482	988
Unrealized Loss	1,711	$ 12
Private Label
Less Than Twelve Months
Estimated Fair Value	7,761
Unrealized Loss	186
Estimated Fair Value	0
Twelve Months or Greater
Unrealized Loss	0
Estimated Fair Value	7,761
Unrealized Loss	$ 186