Condensed Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Income Statement [Abstract]
OIL SALES (Note 8)	$ 135,319	$ 53,142	$ 327,435	$ 173,045
EXPENSES
Operating	37,567	20,721	92,623	84,673
Transportation	3,021	1,286	8,448	8,549
COVID-19 related costs (Note 9)	990	1,108	3,026	1,529
Depletion, depreciation and accretion	38,055	31,340	98,300	131,118
Goodwill impairment (Note 5)	0	0	0	102,581
Asset impairment (Note 5)	0	104,731	0	507,093
General and administrative	6,497	4,562	25,072	16,476
Severance	0	122	919	1,469
Foreign exchange loss	2,650	4,275	15,824	20,094
Derivative instruments loss (gain) (Note 12)	2,603	(2,173)	47,540	(9,417)
Other financial instruments (gain) loss (Note 12)	(13,634)	1,460	(12,425)	61,286
Other loss	0	67	0	67
Interest expense (Note 6)	13,608	14,029	41,355	40,204
EXPENSES	91,357	181,528	320,682	965,722
INTEREST INCOME	0	0	0	345
INCOME (LOSS) BEFORE INCOME TAXES	43,962	(128,386)	6,753	(792,332)
INCOME TAX EXPENSE (RECOVERY)
Current (Note 10)	0	637	(14)	560
Deferred (Note 10)	8,955	(21,202)	26,809	(62,796)
INCOME TAX EXPENSE (RECOVERY)	8,955	(20,565)	26,795	(62,236)
NET AND COMPREHENSIVE INCOME (LOSS)	35,007	(107,821)	(20,042)	(730,096)
NET AND COMPREHENSIVE INCOME (LOSS)	$ 35,007	$ (107,821)	$ (20,042)	$ (730,096)
NET INCOME (LOSS) PER SHARE
BASIC (in dollars per share)	$ 0.10	$ (0.29)	$ (0.05)	$ (1.99)
DILUTED (in dollars per share)	$ 0.10	$ (0.29)	$ (0.05)		$ (1.99)
WEIGHTED AVERAGE SHARES OUTSTANDING - BASIC (Note 7) (in shares)	366,992,802	366,981,556	366,985,646	366,981,556
WEIGHTED AVERAGE SHARES OUTSTANDING - DILUTED (Note 7) (in shares)	367,740,722	366,981,556	366,985,646	366,981,556