Segments and Geographic Area Analysis - Revenues by Geographic Area Presented by Attributing Revenues to Individual Country (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	$ 366,023	$ 349,178	$ 1,139,538	$ 1,208,468
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	171,476	121,895	481,933	414,087
South America [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	58,750	105,614	272,929	333,803
Australia/Asia [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	80,543	56,688	219,103	169,323
Europe [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	48,680	63,117	148,948	253,287
Mexico [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	$ 6,574	$ 1,864	$ 16,625	$ 37,968