Asset Impairments - Additional Information (Detail) $ in Thousands	3 Months Ended				12 Months Ended
	Mar. 31, 2016 Rigs	Dec. 31, 2015 USD ($) Rigs	Sep. 30, 2015 USD ($)	Mar. 31, 2015 USD ($) Rigs ft	Dec. 31, 2015 Rigs
Schedule Of Asset Impairment Charges [Line Items]
Number of rigs evaluated for impairment	10
Impairment of assets | $		$ 499,400	$ 2,600	$ 358,528
Number of additional rigs evaluated for impairment		8			8
Number of additional rigs impaired		9			9
2015 Impaired Rigs [Member]
Schedule Of Asset Impairment Charges [Line Items]
Number of rigs evaluated for impairment				17
Number of rigs impaired				8
Impaired long-lived assets held and used, method for determining fair value	We estimated the fair value of five of the 2015 Impaired Rigs that were cold stacked utilizing a market approach, which required us to estimate the value 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 three remaining 2015 Impaired Rig using an income approach, as they were contracted to customers at that time. The fair value of each of these rigs 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 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.
Impairment of assets | $				$ 358,500
Number of rigs impaired on disposal					17
Number of rigs sold					1
Number of rigs cold stacked	5
Mid-Water Rigs [Member]
Schedule Of Asset Impairment Charges [Line Items]
Number of rigs impaired				7
Ultra-deepwater Drillship [Member]
Schedule Of Asset Impairment Charges [Line Items]
Water depth rated capacity of impaired drillship | ft				7,875
Ultra Deep Water Rigs [Member]
Schedule Of Asset Impairment Charges [Line Items]
Number of additional rigs impaired		1			1
Deep Water Rigs [Member]
Schedule Of Asset Impairment Charges [Line Items]
Number of additional rigs impaired		1			1
Mid-Water Drilling Rigs [Member]
Schedule Of Asset Impairment Charges [Line Items]
Number of additional rigs impaired		2			2
Mid-Water Drilling Rigs [Member] | 2015 Impaired Rigs [Member]
Schedule Of Asset Impairment Charges [Line Items]
Number of rigs sold					6
Jack-ups [Member]
Schedule Of Asset Impairment Charges [Line Items]
Number of additional rigs impaired		5			5
Jack-ups [Member] | 2015 Impaired Rigs [Member]
Schedule Of Asset Impairment Charges [Line Items]
Number of rigs sold	1
Number of rigs marketed for sale	4
Rig with Fair Values Estimated Using Market Approach [Member] | 2015 Impaired Rigs [Member]
Schedule Of Asset Impairment Charges [Line Items]
Total rigs estimated using market approach				5
Rig with Fair Values Estimated Using Income Approach [Member] | 2015 Impaired Rigs [Member]
Schedule Of Asset Impairment Charges [Line Items]
Total rigs estimated using income approach				3