Commitments and Contingencies - Changes in Accrued Environmental Remediation and Related Costs (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Commitments And Contingencies Disclosure [Abstract]
Balance at the beginning of the year	$ 113,133	$ 110,015	$ 113,636
Additions charged to expense, net	5,152	4,370	6,485
Payments, net	(1,627)	(1,252)	(10,106)
Balance at the end of the year	116,658	113,133	110,015
Amounts recognized in the Condensed Consolidated Balance Sheet at the end of the period:
Current liability				$ 13,350	$ 8,668	$ 6,984
Noncurrent liability				103,308	104,465	103,031
Balance at the end of the year	$ 113,133	$ 110,015	$ 113,636	$ 116,658	$ 113,133	$ 110,015