Asset Retirement Obligation (Tables)

12 Months Ended

Dec. 31, 2018

Other Provisions, Contingent Liabilities And Contingent Assets [Abstract]

Asset retirement obligation rollforward

($000s)	2018
Balance, beginning of year	$	12,332
Changes in estimates for asset retirement obligations and additional obligations recognized	843
Obligations settled	(300		)
Asset retirement obligation accretion	270
Effect of movements in foreign exchange rates	(1,032		)
Balance, end of year	$	12,113