Accumulated Other Comprehensive Income (Schedule of Reclassifications) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]
Revenues	$ 2,208,042	$ 1,467,592	$ 2,294,352
Interest expense	(23,972)	(14,432)	(16,485)
Interest and investment income	628	3,808	9,691
Income (loss) before income taxes	339,447	(344,622)	234,047
Provision for (benefit from) income taxes	(1,874)	7	(248)
Net income (loss)	337,573	(344,615)	$ 233,799
Reclassification out of Accumulated Other Comprehensive Income | Derivative instruments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Revenues	0	392
Interest expense	(1,928)	(2,141)
Provision for (benefit from) income taxes	0	0
Net income (loss)	(1,928)	(1,749)
Reclassification out of Accumulated Other Comprehensive Income | Pension, postretirement and other post-employment benefits
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amortization of actuarial gains (losses), net	2,361	(191)
Amortization of prior service credits	190	112
Pension settlement	1,768	896
Provision for (benefit from) income taxes	0	0
Net income (loss)	(403)	1,199
Reclassification out of Accumulated Other Comprehensive Income | Available-for-sale securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Interest and investment income	22	265
Provision for (benefit from) income taxes	0	0
Net income (loss)	$ 22	$ 265