Supplemental Financial Information (Accrued Liabilities) (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Schedule Of Accrued Liabilities [Line Items]
Rig operating expenses	$ 79,629	$ 108,342
Payroll and benefits	80,982	77,055
Deferred revenue	64,012	67,894
Accrued capital project/upgrade costs	48,620	22,725
Interest payable	29,422	21,406
Construction milestone payments		14,600
Personal injury and other claims	11,294	10,536
Other	8,854	13,842
Total	$ 322,813	$ 336,400