Asset retirement obligations (Tables)

9 Months Ended

Sep. 30, 2019

Asset Retirement Obligation Disclosure [Abstract]

Summary of asset retirement obligations

The following table provides a summary of our asset retirement obligation activity:

Balance at January 1, 2019	$	23,147
Liabilities incurred in current period	429
Liabilities settled or disposed in current period	(739		)
Revisions in estimated cash flows	200
Accretion expense	1,089
Balance at September 30, 2019	$	24,126
Less current portion included in accounts payable and accrued liabilities	1,742
Asset retirement obligations, long-term	$	22,384