Income Taxes - Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Components Of Deferred Tax Assets And Liabilities [Abstract]
Accrued liabilities and reserves	$ 146,658	$ 128,553
Allowance for doubtful accounts	18,479	20,134
Inventory	79,363	63,950
Post-retirement benefits	10,288	8,746
Commodity hedges	5,164	1,393
Net operating loss carryforward	59,083	27,131
Tax credit carryforwards	164,132	16,792
Other deferred tax assets	8,508	779
Valuation allowance	(192,295)	(30,104)
Total deferred tax assets	299,380	237,374
Holdbacks and amounts not due under contracts	(12,930)	(10,731)
Intangibles	(171,531)	(167,374)
Property, plant and equipment	(545,890)	(390,575)
Total deferred tax liabilities	(730,351)	(568,680)
Total net deferred tax liabilities	$ (430,971)	$ (331,306)