Asset retirement obligations (Tables)

6 Months Ended

Jun. 30, 2020

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, 2020	$	23,156
Liabilities incurred in current period	84
Liabilities settled or disposed in current period	(419)
Revisions in estimated cash flows	49
Accretion expense	649
Balance at June 30, 2020	$	23,519
Less current portion included in accounts payable and accrued liabilities	2,107
Asset retirement obligations, long-term	$	21,412