DECOMMISSIONING LIABILITIES (Tables)

12 Months Ended

Dec. 31, 2018

Other Provisions, Contingent Liabilities And Contingent Assets [Abstract]

Disclosure of decommissioning liabilities

($000s)	2018			2017
Balance, beginning of year	$	60,611		$	62,844
Incurred on development activities	678			1,501
Acquired through asset acquisitions	3,462			—
Revisions on estimates	37			3,210
Decommissioning costs incurred	(2,242		)	(2,758		)
Reversed on dispositions	—			(5,473		)
Accretion expense	1,328			1,287
Balance, end of year	$	63,874		$	60,611