Asset Retirement Obligations (Tables)

12 Months Ended

Dec. 31, 2016

Asset Retirement Obligation Disclosure [Abstract]

Summary of Asset Retirement Obligation

Changes to the Company’s asset retirement obligation are summarized below:

	December 31,	December 31,
	2016	2015
	(thousands of dollars)
Balance, beginning  of period	$              4,468	$         4,196
Liabilities settled	(54)	(178)
Accretion expense	480	450
Balance, end of period	4,894	4,468
Less:  Included in liabilities held for sale	(105)	(105)
Less:  Current portion	(121)	(121)
Non-current portion	$              4,668	$         4,242