Drilling and Other Property and Equipment - Summary of Cost and Accumulated Depreciation of Drilling and Other Property and Equipment (Detail) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Property and equipment	$ 7,183,119	$ 8,161,045
Less: accumulated depreciation	(2,940,013)	(3,008,217)
Drilling and other property and equipment, net	4,243,106	5,152,828
Drilling Rigs and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	7,026,827	8,004,489
Land and Buildings [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	64,076	64,267
Office Equipment and Other [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	$ 92,216	$ 92,289