Financial Instruments and Fair Value Disclosures - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Accounts receivable expected to be collected within one year	$ 17,200,000	$ 95,800,000
Net profits interest percent	27.00%
Allowance for bad debts	5,458,000	6,867,000	31,908,000	41,698,000
Petroleo Brasileiro S.A. [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Accounts receivable due from major customer	116,400,000	110,400,000
Percentage of accounts receivable due from major customer	24.00%	20.00%
OGX Petroleo e Gas Ltda [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Accounts receivable due from major customer	80,300,000	69,400,000
Percentage of accounts receivable due from major customer	17.00%	12.00%
5.70% Senior Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate of senior notes	5.70%	5.70%
5.875% Senior Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate of senior notes	5.875%	5.875%
4.875% Senior Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate of senior notes	4.875%	4.875%
5.15% Senior Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate of senior notes	5.15%	5.15%
Level 1 [Member] | Cash Held in Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of investments	284,900,000	303,900,000
Level 1 [Member] | U.S. Treasury Bills [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of investments	$ 1,149,900,000	$ 902,000,000