Income Taxes - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jan. 01, 2018
Income Tax Disclosure [Abstract]
Tax Cuts and Jobs Act of 2018, provisional tax benefit recognized	$ (24,900)	$ (109,000)
Reserves for uncertain tax positions	183,786	191,860
Related tax benefits	1,008	1,008	$ 1,008
Amount provision for income taxes reduced if reserves not realized	$ 183,800
Operational period	12 months
Interest and penalties resulted in an income tax expense	$ 5,100	4,700	$ 2,700
Provision for non-cash items related to impairment of three rigs	35,600
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Tax Cuts and Jobs Act of 2018, additional tax benefit recognized	$ 24,900
Accounting Standards Update 2016-16
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reclassification due to new accounting standard		$ 148,393
Other assets | Accounting Standards Update 2016-16
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reclassification due to new accounting standard				$ 148,400