Income tax (Tables)

12 Months Ended

Dec. 31, 2018

Statements [Line Items]

Disclosure of detailed information about effective income tax expense recovery [Table Text Block]

	Year ended December 31,
	2018		2017
	$		$
Average statutory tax rate	27%		26%
Income (loss) before income taxes	(128,704	)	30,388
Expected income tax expense (recovery)	(34,750	)	7,901
Increase in income tax expense (recovery) resulting from:
Loss associated with loss of control	47,312		-
Permanent differences	(608	)	(184	)
True-up prior year balances	(564	)	3,688
Effect of differences in tax rate in foreign jurisdictions	(7,164	)	3,214
Change in unrecognized tax assets	7,240		9,099
Withholding tax	1,079		1,301
Foreign exchange and other	(36	)	(944	)
Income tax expense	12,509		24,075

Disclosure of deferred taxes [Table Text Block]

	Year ended December 31,
	2018	2017
	$	$
Mineral properties, plant and equipment	-	(48,475	)
Asset retirement provisions	-	6,694
	-	(41,781	)
Deferred tax assets	-	6,694
Deferred tax liabilities	-	(48,475	)

Disclosure of temporary difference, unused tax losses and unused tax credits [Table Text Block]

	Year ended December 31,
	2018	2017
	$	$
Mineral properties, plant and equipment	50	11,440
Share issuance costs	146	302
Investment in associate	275	275
Asset retirement provision	-	4,083
Unrealized foreign exchange	-	(788	)
Foreign exchange loss carried forward	-	509
Capital losses	2,476	-
Non-capital losses carried forward	12,689	33,464
Total	15,636	49,285