Accumulated Other Comprehensive Income (Loss) - Schedule of reclassifications (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Accumulated Other Comprehensive Income (Loss)
Interest expense	$ (3,933)	$ (3,537)	$ (8,249)	$ (7,663)
Net loss resulting from early retirement of debt				1,126
Interest and investment income	5,403	4,201	11,503	7,537
Total before tax	16,835	90,273	76,507	325,519
Provision for income taxes	2,002	12,920	5,721	50,058
Net Income (Loss)	14,833	77,353	70,786	275,461
Pension, postretirement and other post-employment benefits
Accumulated Other Comprehensive Income (Loss)
Provision for income taxes			854
Available-for-sale securities
Accumulated Other Comprehensive Income (Loss)
Provision for income taxes			(2)
Reclassification out of Accumulated Other Comprehensive Income | Pension, postretirement and other post-employment benefits
Accumulated Other Comprehensive Income (Loss)
Amortization of actuarial gains, net 1	2,006	2,858	4,012	5,717
Amortization of prior service credits		37		73
Total before tax	2,006	2,895	4,012	5,790
Provision for income taxes	427	636	854	1,272
Net Income (Loss)	1,579	2,259	3,158	4,518
Reclassification out of Accumulated Other Comprehensive Income | Available-for-sale securities
Accumulated Other Comprehensive Income (Loss)
Interest and investment income	(1)	1	8	(21)
Provision for income taxes	(3)	(3)	(2)	(8)
Net Income (Loss)	$ 2	$ 4	$ 10	$ (13)