Financial Instruments and Fair Value Disclosures - Additional Information (Detail) (USD $)	3 Months Ended	9 Months Ended																12 Months Ended	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2013 Customer	Sep. 30, 2013 Customer	Sep. 30, 2012	Dec. 31, 2012	Sep. 30, 2013 5.70% Senior Notes [Member]	Dec. 31, 2012 5.70% Senior Notes [Member]	Sep. 30, 2013 5.875% Senior Notes [Member]	Dec. 31, 2012 5.875% Senior Notes [Member]	Sep. 30, 2013 4.875% Senior Notes [Member]	Dec. 31, 2012 4.875% Senior Notes [Member]	Sep. 30, 2013 5.15% Senior Notes [Member]	Dec. 31, 2012 5.15% Senior Notes [Member]	Sep. 30, 2013 Level 1 [Member] Cash Held in Money Market Funds [Member]	Dec. 31, 2012 Level 1 [Member] Cash Held in Money Market Funds [Member]	Sep. 30, 2013 Level 1 [Member] Time Deposits [Member]	Sep. 30, 2013 Level 1 [Member] U.S. Treasury Bills [Member]	Dec. 31, 2012 Level 1 [Member] U.S. Treasury Bills [Member]	Dec. 31, 2012 Net Profits Interest [Member]	Sep. 30, 2013 Ogx and Niko Resources [Member] Customer	Sep. 30, 2013 Accounts Receivable [Member] Petroleo Brasileiro S.A. [Member] Customer Concentration Risk [Member]	Dec. 31, 2012 Accounts Receivable [Member] Petroleo Brasileiro S.A. [Member] Customer Concentration Risk [Member]	Dec. 31, 2012 Accounts Receivable [Member] OGX Petroleo e Gas Ltda [Member] Customer Concentration Risk [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Accounts receivable due from major customer	$ 424,808,000	$ 424,808,000		$ 499,660,000														$ 17,200,000		$ 120,400,000	$ 116,400,000	$ 80,300,000
Percentage of accounts receivable due from major customer																				28.00%	24.00%	17.00%
Number of customers	2	2																	2
Allowance for bad debts	28,152,000	28,152,000		5,458,000
Bad debt expense	22,600,000	22,600,000																	22,600,000
Net profits interest percent																		27.00%
Fair value of investments													385,600,000	284,900,000	20,000,000	800,000,000	1,149,900,000
Transfers between fair value levels		$ 0	$ 0
Interest rate of senior notes					5.70%	5.70%	5.875%	5.875%	4.875%	4.875%	5.15%	5.15%