Consolidated Joint Ventures (Details) $ in Thousands		12 Months Ended
	Dec. 03, 2019 USD ($)	Dec. 31, 2019 USD ($) joint_venture rig	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Schedule Of Equity Method Investments [Line Items]
Percent of interest in joint ventures		50.00%
Number of joint ventures | joint_venture		2
Number of bully class drillships | rig		2
Percentage of dividends paid to joint venture partner		50.00%
Loss on impairment		$ 615,294	$ 802,133	$ 121,639
Cash and cash equivalents		104,621	375,232
Bully I
Schedule Of Equity Method Investments [Line Items]
Ownership percentage	50.00%
Bully II
Schedule Of Equity Method Investments [Line Items]
Ownership percentage	50.00%
Bully Joint Venture
Schedule Of Equity Method Investments [Line Items]
Payments to Acquire Interest in Joint Venture	$ 106,700
Dividends approved and paid		50,200	55,200	$ 113,800
Carrying amount of the drillships			700,000
Loss on impairment		265,000	250,300
Cash and cash equivalents			45,200
Floaters | Bully Joint Venture
Schedule Of Equity Method Investments [Line Items]
Loss on impairment		$ 595,500	$ 550,300
Subsidiary Of Royal Dutch Shell PLC
Schedule Of Equity Method Investments [Line Items]
Proceeds from contract termination	$ 166,900