Components of Change in Other Assets and Liabilities Net (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Supplemental Cash Flow Elements [Abstract]
Other current and noncurrent assets	$ (9,032)	$ (22,914)
Accrued salaries, benefits and payroll taxes	(13,833)	(21,335)
Accrued insurance and other taxes	(12,545)	(10,557)
Accrued income taxes	7,357	3,330
Accrued pension, postretirement and postemployment benefits	6,273	6,421
Other current and noncurrent liabilities	11,359	21,385
Change in other assets and liabilities, net	$ (10,421)	$ (23,670)