Drilling and Other Property and Equipment - Summary of Cost and Accumulated Depreciation of Drilling and Other Property and Equipment (Detail) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Property and equipment	$ 6,682,228	$ 7,111,718
Less: accumulated depreciation	(2,781,814)	(2,988,909)
Drilling and other property and equipment, net	3,900,414	4,122,809
Drilling Rigs and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	6,558,577	6,987,630
Land and Buildings [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	40,425	41,072
Office Equipment and Other [Member]
Property, Plant and Equipment [Line Items]
Property and equipment	$ 83,226	$ 83,016