Asset Impairments - Additional Information (Detail) $ in Thousands		1 Months Ended	3 Months Ended					12 Months Ended
	Feb. 19, 2016 USD ($) Rigs	Feb. 29, 2016 USD ($)	Dec. 31, 2015 USD ($) Rigs	Sep. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2014 USD ($) Rigs	Sep. 30, 2014 USD ($) Rigs	Dec. 31, 2015 USD ($) Rigs	Dec. 31, 2014 USD ($) Rigs	Dec. 31, 2013 USD ($)
Schedule Of Asset Impairment Charges [Line Items]
Impairment of assets | $			$ 499,400	$ 2,600	$ 358,500			$ 860,441	$ 109,462
Carrying value of impaired rigs | $			$ 175,400					175,400
Proceeds from sale of rigs | $								$ 13,049	18,318	$ 4,900
Number of rigs sold for scrap								9
Subsequent Event [Member]
Schedule Of Asset Impairment Charges [Line Items]
Proceeds from sale of rigs | $		$ 8,000
2014 Impaired Rigs [Member]
Schedule Of Asset Impairment Charges [Line Items]
Number of rigs evaluated for impairment							6
Impaired long-lived assets held and used, method for determining fair value								We determined the fair value of the 2014 Impaired Rigs by applying a combination of income and market approaches which were representative of Level 3 fair value measurements due to the significant level of estimation involved and the lack of transparency as to the inputs used.
Carrying value of impaired rigs | $						$ 9,400			$ 9,400
Additional rigs evaluated for impairment						6			6
Number of rigs sold for scrap						2
2015 Impaired Rigs [Member]
Schedule Of Asset Impairment Charges [Line Items]
Number of rigs evaluated for impairment			25					25
Number of rigs impaired			17					17
Impaired long-lived assets held and used, method for determining fair value								We estimated the fair value of 16 of the 2015 Impaired Rigs utilizing a market approach, which required us to estimate the exchange price that would be received for each rig in the principal or most advantageous market for that rig in an orderly transaction between market participants. Such estimates were based on various inputs, including historical contracted sales prices for similar rigs in our fleet, nonbinding quotes from rig brokers and/or indicative bids, where applicable. We estimated the fair value of the one remaining 2015 Impaired Rig using an income approach, as we determined that the most likely use for this rig would be to cold stack the rig and reintroduce it into the market at a later date. The fair value of this rig was estimated based on a calculation of the rig’s discounted future net cash flows over its remaining economic life, which utilized significant unobservable inputs, including, but not limited to, assumptions related to estimated dayrate revenue, rig utilization, estimated equipment upgrade and regulatory survey costs, as well as estimated proceeds that may be received on ultimate disposition of the rig. Our fair value estimates are representative of Level 3 fair value measurements due to the significant level of estimation involved and the lack of transparency as to the inputs used.
Impairment of assets | $			$ 499,400	$ 2,600	$ 358,500			$ 860,400
Number of rigs cold stacked			6					6
Carrying value of impaired rigs | $			$ 175,400					$ 175,400
2015 Impaired Rigs [Member] | Rig with Fair Values Estimated Using Market Approach [Member]
Schedule Of Asset Impairment Charges [Line Items]
Total rigs estimated using market approach			16					16
2015 Impaired Rigs [Member] | Rig with Fair Values Estimated Using Income Approach [Member]
Schedule Of Asset Impairment Charges [Line Items]
Number of rigs with fair values estimated using income approach			1					1
Ultra-Deepwater Rigs [Member]
Schedule Of Asset Impairment Charges [Line Items]
Number of rigs impaired			2					2
Deepwater Rigs [Member]
Schedule Of Asset Impairment Charges [Line Items]
Number of rigs impaired			1					1
Mid-Water Rigs [Member]
Schedule Of Asset Impairment Charges [Line Items]
Number of rigs impaired			9					9
Impairment of assets | $							$ 109,500
Number of rigs sold								5
Number of rigs subject to scrap							6
Jack-ups [Member]
Schedule Of Asset Impairment Charges [Line Items]
Number of rigs impaired			5					5
Carrying value of impaired rigs | $			$ 14,200					$ 14,200
Jack-ups [Member] | Subsequent Event [Member]
Schedule Of Asset Impairment Charges [Line Items]
Number of rigs sold	1
Proceeds from sale of rigs | $	$ 8,000
Jack-ups [Member] | Rig with Fair Values Estimated Using Market Approach [Member]
Schedule Of Asset Impairment Charges [Line Items]
Number of rigs held for sale			5					5