Income Taxes - Principal Components Of The Company's Deferred Tax Assets And Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Deferred income tax assets:
Accruals not yet tax deductible	$ 133,150	$ 142,100
Pension and postretirement healthcare plan obligations	0	6,499
Stock compensation	10,908	9,619
Net operating loss and research & development tax credit carryforwards	60,401	55,857
Other	66,245	78,051
Deferred tax assets, gross	270,704	292,126
Valuation allowance	(33,596)	(38,072)
Deferred tax assets, net	237,108	254,054
Deferred income tax liabilities:
Depreciation, tax in excess of book	(66,301)	(74,579)
Pension and postretirement healthcare plan obligations	(67,741)	0
Other	(29,405)	(29,544)
Deferred tax liabilities, net	(163,447)	(104,123)
Total	$ 73,661	$ 149,931