Provisions (Tables)

12 Months Ended

Dec. 31, 2017

Dec. 31, 2016

Statement [Line Items]

Disclosure of changes in provisions [Table Text Block]

		Decommis-
		sioning,
		restoration			Deferred			Restricted
		and similar			share units			share units 1
		liabilities			(note 23a	)		(note 23a	)		Other			Total
Balance, January 1, 2017	$	177,296		$	3,933		$	11,052		$	1,788		$	194,069
Net additional provisions made		6,485			868			7,327			202			14,882
Amounts used		(69	)		(638	)		(5,491	)		(937	)		(7,135	)
Unwinding of discount (note 5f)		4,159			-			-			-			4,159
Effect of change in discount rate		2,658			-			-			-			2,658
Effect of foreign exchange		9,512			346			1,194			95			11,147
Effect of change in share price		-			2,114			5,327			287			7,728
Balance, December 31, 2017	$	200,041		$	6,623		$	19,409		$	1,435		$	227,508

		Decommis-
		sioning,
		restoration			Deferred			Restricted
		and similar			share units			share units
		liabilities			(note 23a	)		(note 23a	) 1		Other			Total
Balance, January 1, 2016	$	147,035		$	2,803		$	4,388		$	-		$	154,226
Net additional provisions made		30,038			1,018			6,348			1,922			39,326
Amounts used		(894	)		(1,078	)		(2,736	)		(430	)		(5,138	)
Unwinding of discount (note 5f)		2,586			-			-			-			2,586
Effect of change in discount rate		(4,189	)		-			-			-			(4,189	)
Effect of foreign exchange		2,720			97			(47	)		20			2,790
Effect of change in share price		-			1,093			3,099			276			4,468
Balance, December 31, 2016	$	177,296		$	3,933		$	11,052		$	1,788		$	194,069

Disclosure of detailed information about provisions [Table Text Block]

Current (note 13)	$	2,344	$	6,623	$	17,119	$	1,284	$	27,370
Non-current		197,697		-		2,290		151		200,138
	$	200,041	$	6,623	$	19,409	$	1,435	$	227,508

Current (note 13)	$	1,054	$	3,933	$	8,451	$	929	$	14,367
Non-current		176,242		-		2,601		859		179,702
	$	177,296	$	3,933	$	11,052	$	1,788	$	194,069