Consolidated Joint Ventures - Additional Information (Detail) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Sep. 30, 2014 USD ($)	Jun. 30, 2014 USD ($)	Mar. 31, 2014 USD ($)	Dec. 31, 2015 USD ($) Rig JointVenture	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Dec. 31, 2012 USD ($)
Schedule Of Equity Method Investments [Line Items]
Percent of interest in joint ventures									50.00%
Number of joint ventures acquired | JointVenture									2
Number of bully class drillships | Rig									2
Dividend paid to joint venture partner									$ 72,000	$ 80,000	$ 105,000
Carrying amount of the drillships	$ 1,400,000				$ 1,400,000				1,400,000	1,400,000
Cash held by Bully joint venture	512,245				68,510				512,245	68,510	114,458	$ 282,092
Operating revenues	857,684	$ 896,671	$ 793,555	$ 804,342	804,740	$ 828,796	$ 803,781	$ 795,187	3,352,252	3,232,504	2,538,143
Net income									583,201	83,316	850,406
Bully Joint Venture [Member]
Schedule Of Equity Method Investments [Line Items]
Dividend paid by Bully Joint Venture Partners									143,000	160,000	211,000
Cash held by Bully joint venture	$ 50,000				$ 47,000				50,000	47,000
Operating revenues									334,000	372,000	355,000
Net income									$ 154,000	$ 157,000	$ 145,000