Income Taxes - Deferred Income Tax Assets (Liabilities) (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Deferred income tax assets:
Accrued liabilities	$ 93,491	$ 104,675
Retirement plans and postretirement benefits	34,777	33,259
Share-based compensation	13,322	15,386
Receivables and inventories	8,187	11,061
Intangible assets	0	4,131
Derivative financial instruments	0	3,990
Net operating loss carryforwards	34,478	30,799
Tax credit carryforwards	8,890	5,026
Valuation allowances	(12,048)	(10,968)
Deferred income tax assets	181,097	197,359
Deferred income tax liabilities:
Property, plant and equipment	(208,559)	(208,485)
Intangible assets	(29,356)	0
Derivative financial instruments	(916)	0
Cancellation of debt	(5,576)	(8,411)
Other	(3,458)	(1,162)
Deferred income tax liabilities	(247,865)	(218,058)
Net deferred income tax liability	(66,768)	(20,699)
Deferred tax assets related to uncertain tax positions	$ 8,800	$ 8,700