Other Financial Statement Disclosures (Narrative) (Details) $ in Thousands	1 Months Ended	3 Months Ended			9 Months Ended
	Feb. 28, 2014 USD ($)	Sep. 30, 2015 USD ($) drilling_unit	Jun. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)
Supplemental Cash Flow Information
Accrued capital expenditures					$ 36,500	$ 48,900
Interest capitalized in connection with rig construction projects				$ 15,500	$ 16,200	$ 46,000
Income Taxes
Effective tax rate		(12.20%)		(47.30%)	256.20%	(21.00%)
Additional valuation allowance recorded					$ 75,400
Litigation Settlement
Proceeds from litigation settlements						$ 20,900
Material Charges and Other Operating Expenses
Carrying value of property, plant, and equipment		$ 7,468,718			7,468,718		$ 7,432,212
Impairment charges					329,781	8,300
Jack-up Drilling Rigs [Member]
Material Charges and Other Operating Expenses
Number of drilling units impaired | drilling_unit		10
Carrying value of property, plant, and equipment		$ 458,000			458,000
Impairment charges		329,800
Aircraft [Member]
Material Charges and Other Operating Expenses
Carrying value of property, plant, and equipment				$ 12,700		12,700
Impairment charges						8,300
Rowan land rig [Member]
Discontinued Operations
Net assets of discontinued operations	$ 4,100
Assets of discontinued operations	24,200
Deferred revenues classified as liabilities of discontinued operations	20,100
Proceeds from sale of rig	$ 6,000
Gain (loss) on disposals of property and equipment						$ 4,000
HS Ocean Group Ltd. [Member] | Loss on Purchase Contract [Member]
Material Charges and Other Operating Expenses
Increase in estimated liability		2,600	$ 5,000		$ 7,600
Foreign Exchange Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments
Typical term of derivative contracts					1 month
Notional amount		20,200			$ 20,200
Loss on outstanding contracts					45
Foreign Exchange Contract [Member] | Norwegian kroner | Not Designated as Hedging Instrument [Member]
Derivative Instruments
Notional amount		7,100			7,100
Foreign Exchange Contract [Member] | Saudi riyals | Not Designated as Hedging Instrument [Member]
Derivative Instruments
Notional amount		6,200			6,200
Foreign Exchange Contract [Member] | British pounds sterling | Not Designated as Hedging Instrument [Member]
Derivative Instruments
Notional amount		5,300			5,300
Foreign Exchange Contract [Member] | Euros | Not Designated as Hedging Instrument [Member]
Derivative Instruments
Notional amount		1,000			1,000
Foreign Exchange Contract [Member] | Other currencies | Not Designated as Hedging Instrument [Member]
Derivative Instruments
Notional amount		$ 600			$ 600