Other Noncurrent Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Other Liabilities Disclosure [Abstract]
Pension and retiree medical obligations	$ 92,308	$ 99,417
Transition tax payable	14,128	14,208
Liability for uncertain tax positions	773	1,071
Deferred revenue	31,025	30,354
Lease liability	96,927	94,250
Other	22,883	27,497
Total other noncurrent liabilities	$ 258,044	$ 266,797