Segments and Geographic Area Analysis - Revenues from Major Customers that Contributed More than 10% of Total Revenues (Detail) - Revenues [Member] - Customer Concentration Risk [Member]	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenue, Major Customer [Line Items]
Percentage of revenues from major customers	10.00%	10.00%	10.00%
Hess Corporation [Member]
Revenue, Major Customer [Line Items]
Percentage of revenues from major customers	28.90%	25.00%	16.00%
Occidental (formerly Anadarko) [Member]
Revenue, Major Customer [Line Items]
Percentage of revenues from major customers	20.60%	33.80%	24.90%
Petrobras Brasileiro S.A. [Member]
Revenue, Major Customer [Line Items]
Percentage of revenues from major customers	19.50%	15.80%	18.90%
BP [Member]
Revenue, Major Customer [Line Items]
Percentage of revenues from major customers	3.10%	10.50%	15.80%