Consolidated Statements of Operations - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Statement [Abstract]
OIL AND NATURAL GAS SALES (NOTE 5)	$ 289,269,000	$ 276,011,000	$ 559,398,000
EXPENSES
Operating	86,925,000	75,565,000	89,753,000
Transportation	31,776,000	40,204,000	24,196,000
Depletion, depreciation and accretion (Note 5)	139,535,000	176,386,000	185,877,000
Asset impairment (Notes 5 and 7)	616,649,000	323,918,000	265,126,000
General and administrative (Note 5)	33,218,000	32,353,000	51,249,000
Transaction (Note 3)	7,325,000	0	0
Severance (Note 15)	1,319,000	8,990,000	0
Equity tax (Note 11)	3,098,000	3,769,000	0
Foreign exchange gain	(1,469,000)	(17,242,000)	(39,535,000)
Financial instruments loss (Note 14)	10,279,000	2,027,000	4,722,000
Other gain (Note 3)	(929,000)	(502,000)	(2,000,000)
Interest expense (Notes 5 and 8)	14,145,000	0	0
Total expenses	941,871,000	645,468,000	579,388,000
INTEREST INCOME (NOTE 5)	2,368,000	1,369,000	2,856,000
LOSS FROM CONTINUING OPERATIONS BEFORE INCOME TAXES (NOTE 5)	(650,234,000)	(368,088,000)	(17,134,000)
INCOME TAX (EXPENSE) RECOVERY
Current (Note 11)	(20,122,000)	(15,383,000)	(92,865,000)
Deferred (Note 11)	204,791,000	115,442,000	(34,350,000)
Income tax (expense) recovery	184,669,000	100,059,000	(127,215,000)
LOSS FROM CONTINUING OPERATIONS	(465,565,000)	(268,029,000)	(144,349,000)
Loss from discontinued operations, net of income taxes (Note 4)	0	0	(26,990,000)
NET LOSS AND COMPREHENSIVE LOSS	$ (465,565,000)	$ (268,029,000)	$ (171,339,000)
BASIC AND DILUTED
LOSS FROM CONTINUING OPERATIONS (in dollars per share)	$ (1.45)	$ (0.94)	$ (0.51)
LOSS FROM DISCONTINUED OPERATIONS, NET OF INCOME TAXES (in dollars per share)	0.00	0.00	(0.09)
NET LOSS (in dollars per share)	$ (1.45)	$ (0.94)	$ (0.60)
WEIGHTED AVERAGE SHARES OUTSTANDING - BASIC AND DILUTED (in shares)	320,851,538	285,333,869	284,715,785