Other Non-Current Liabilities - Statement of Composition of Other Non Current Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Other Liabilities Disclosure [Abstract]
Deferred revenue	$ 1,539	$ 1,863
Environmental and legal matters	21,888	22,703
Deferred compensation liability	51,890	53,133
Pension liability	25,632	29,494
Other non-current liabilities	29,484	12,160
Total other non-current liabilities	$ 130,433	$ 119,353