Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Reserves	$ 4,625	$ 4,720
Environmental	20,868	7,211
Compensation	8,950	8,250
Post-retirement benefits	18,318	19,476
Research & development expenses	6,949	8,925
Inventories	1,464	3,445
Other	993	605
Tax carryforwards	14,438	8,413
Deferred tax assets	76,605	61,045
Valuation allowance	(4,066)	(3,773)
Net deferred tax assets	72,539	57,272
Property	(81,837)	(84,009)
Intangible assets	(16,561)	(17,748)
Pension	(29,041)	(26,885)
Deferred tax liabilities	(127,439)	(128,642)
Net deferred tax liabilities	$ (54,900)	$ (71,370)