Business Combinations (Details)	12 Months Ended
	Dec. 31, 2011 USD ($)	Dec. 31, 2010 USD ($)	Dec. 31, 2009 USD ($)	Dec. 31, 2011 Petrolifera [Member] USD ($)	Dec. 31, 2011 Petrolifera [Member] CAD	Dec. 31, 2011 Solana [Member] Warrants Canadian Dollars [Member]
Business Acquisition [Line Items]
Effective date of acquisition				2011-03-18	2011-03-18
Date of acquisition agreement				2011-01-17	2011-01-17
Shares of acquirer's common stock issued to holder of each share of acquired entity (in shares)				0.1241	0.1241
Shares of acquirer's common stock issued to holder of each common stock warrant of acquired entity (in shares)				0.1241	0.1241
Expiration date of stock warrants issued in business acquisition				2011-08-28	2011-08-28
Exercise price of common warrants issued by acquirer in business acquisition (in Canadian dollars per share)					9.67
Acquirer's common shares issued in acquisition (in shares)				18,075,247	18,075,247
Par value of common shares issued in acquisition (in dollars per share)	$ 0.001	$ 0.001		$ 0.001
Replacement Warrants issued in business acquisition (in shares)				4,125,036	4,125,036
Business acquisition acquired entity security holders ownership in new entity (in hundredths)				6.60%	6.60%
Business acquisition acquirer's security holders ownership in new entity (in hundredths)				93.40%	93.40%
Fair Value Assumptions, Methodology Used				fair value of the Replacement Warrants was estimated on the Acquisition Date using the Black-Scholes option pricing model with the following assumptions	fair value of the Replacement Warrants was estimated on the Acquisition Date using the Black-Scholes option pricing model with the following assumptions
Total consideration for acquisition	$ 143,044,000			$ 143,044,000
Revenue and other income	606,602,000	427,137,000
Net income	94,094,000	7,557,000
Net income per share -basic (in dollars per share)	$ 0.34	$ 0.03
Net income per share - diluted (in dollars per share)	$ 0.33	$ 0.03
Investments in Notes Received in Exchange at Fair Value				22,500,000
Face Value of Asset Back Commercial Paper Given in Exchange				31,300,000
Proceeds on sale of asset backed commercial paper	22,679,000	0	0	22,679,000
Financial instruments (gain) loss	1,522,000	44,000	(190,000)	1,522,000
ABCP line of credit					23,200,000
Repayment of debt from cash flow					22,500,000
Second line of credit					5,000,000
Face value of second line of credit collateral				(master asset vehicles Classes 1 & 2 “MAV IA 1 & 2” notes with a face value of 6.6 million)	(master asset vehicles Classes 1 & 2 “MAV IA 1 & 2” notes with a face value of 6.6 million)
Reserve-backed credit facility assumed in acquisition				31,300,000
Total debt repayment				54,100,000
Business acquisition transaction costs excluded from Pro Forma and recorded in administrative expense	4,400,000
Gain on acquisition excluded from pro forma results	21,700,000
Oil and natural gas sales from acquisition for the period subsequent to the acquisition date	32,500,000
Loss after tax from the acquisition in the period since the acquisition date	8,200,000
Gain on fair value of the expired Replacement Warrants				1,300,000
Cash Acquired in Business Acquisition	7,747,000	0	0	7,747,000
Accounts Receivable Acquired in Business Acquisition				6,400,000
Fair value of options and warrants [Abstract]
Exercise price (in Canadian dollars per share)					9.67
Risk-free interest rate (in hundredths)				1.30%	1.30%
Expected life (in years)				.45 Y	.45 Y
Volatility (in hundredths)				44.00%	44.00%
Expected annual dividend per share
Fair value per warrant (in Canadian dollars per share)					0.32
Consideration Transferred:
Common Shares Issued Net of Share Issue Costs				141,690,000
Replacement warrants (in shares)				1,354,000
Total Purchase Price	143,044,000			143,044,000
Oil and gas properties
Proved				58,457,000
Unproved				161,278,000
Other Long Term Assets				4,417,000
Net Working Capital (including cash acquired of $ 7.7 million and accounts receivable of $ 6.4 million )				(17,223,000)
Asset Retirement Obligation				(4,901,000)
Bank Debt				(22,853,000)
Other Long Term Liabilities				(14,432,000)
Gain on acquisition				(21,699,000)
Total Purchase Price	$ 143,044,000			$ 143,044,000