Components of Change in Other Assets and Liabilities Net (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Supplemental Cash Flow Elements [Abstract]
Other current and noncurrent assets	$ (29,342)	$ (3,997)
Accrued salaries, benefits and payroll taxes	(6,234)	413
Accrued insurance and other taxes	10,230	5,041
Accrued income taxes	16,393	693
Accrued pension, postretirement and postemployment benefits	(5,807)	(21,624)
Other current and noncurrent liabilities	49,244	(1,437)
Change in other assets and liabilities, net	$ 34,484	$ (20,911)