Business Segment and Significant Customer Information - Schedule of Property,Plant and Equipment,Net by Country (Detail) - USD ($) $ in Thousands		Mar. 31, 2018	Dec. 31, 2017
Revenues From External Customers And Long Lived Assets [Line Items]
Total property and equipment		$ 745,169	$ 763,191
Congo
Revenues From External Customers And Long Lived Assets [Line Items]
Total property and equipment		250,817	256,200
India
Revenues From External Customers And Long Lived Assets [Line Items]
Total property and equipment		152,470	155,362
Malaysia
Revenues From External Customers And Long Lived Assets [Line Items]
Total property and equipment			103,603
South Africa
Revenues From External Customers And Long Lived Assets [Line Items]
Total property and equipment		175,711	179,468
Other countries
Revenues From External Customers And Long Lived Assets [Line Items]
Total property and equipment	[1]	$ 166,171	$ 68,558

[1] Other countries represent countries in which we individually had property and equipment, net, representing less than 10% of total property and equipment, net.