Other Comprehensive Income (Loss) (AOCI Reclassifications) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Accumulated Other Comprehensive Income (Loss) [Line Items]
Defined benefit pension plan adjustments/Unrealized loss in fair value of investment adjustments	$ (3,058)	$ (1,020)	$ (9,475)	$ (4,717)
Income tax benefit	194	(43,718)	(47,918)	(47,607)
Net of tax	37,534	63,003	86,730	84,637
Defined benefit pension plan adjustments | Reclassification out of Accumulated Other Comprehensive Income
Accumulated Other Comprehensive Income (Loss) [Line Items]
Defined benefit pension plan adjustments/Unrealized loss in fair value of investment adjustments	411	638	826	1,277
Income tax benefit	(115)	(181)	(229)	(362)
Net of tax	296	457	597	915
Unrealized loss in fair value of investment adjustments | Reclassification out of Accumulated Other Comprehensive Income
Accumulated Other Comprehensive Income (Loss) [Line Items]
Defined benefit pension plan adjustments/Unrealized loss in fair value of investment adjustments	55	31	85	42
Income tax benefit	(12)	(7)	(18)	(9)
Net of tax	$ 43	$ 24	$ 67	$ 33