Supplemental Financial Information (Prepaid Expenses and Other Current Assets) (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Rig spare parts and supplies	$ 54,735	$ 52,637
Deferred mobilization costs	43,967	74,659
Prepaid insurance	20,424	12,417
Deferred tax assets	6,800	6,800
Prepaid taxes	7,308	37,612
FOREX contracts	4,383	1,262
Other	5,824	7,183
Total	$ 143,441	$ 192,570