Consolidated Statements of Operations and Retained Earnings (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
REVENUE AND OTHER INCOME
Oil and natural gas sales	$ 596,191	$ 373,286	$ 262,629
Interest income	1,216	1,174	1,087
Total revenue and other income	597,407	374,460	263,716
EXPENSES
Operating	86,497	59,446	40,784
Depletion, depreciation, accretion and impairment (Note 6)	231,235	163,573	135,863
General and administrative	60,389	40,241	28,787
Equity tax (Note 9)	8,271	0	0
Financial instruments (gain) loss	(1,522)	(44)	190
Gain on acquisition (Note 3 and 12)	(21,699)	0	0
Foreign exchange (gain) loss	(11)	16,838	19,797
Total expenses	363,160	280,054	225,421
INCOME BEFORE INCOME TAXES	234,247	94,406	38,295
Income tax expense (Note 9)	(107,330)	(57,234)	(24,354)
NET INCOME AND COMPREHENSIVE INCOME	126,917	37,172	13,941
RETAINED EARNINGS, BEGINNING OF YEAR	58,097	20,925	6,984
RETAINED EARNINGS, END OF YEAR	$ 185,014	$ 58,097	$ 20,925
NET INCOME PER SHARE - BASIC (in dollars per share)	$ 0.46	$ 0.15	$ 0.06
NET INCOME PER SHARE - DILUTED (in dollars per share)	$ 0.45	$ 0.14	$ 0.05
WEIGHTED AVERAGE SHARES OUTSTANDING - BASIC (Note 7) (in shares)	273,491,564	253,697,076	241,258,568
WEIGHTED AVERAGE SHARES OUTSTANDING - DILUTED (Note 7) (in shares)	281,287,002	264,304,831	253,590,103