ASSET RETIREMENT OBLIGATIONS (Tables)

12 Months Ended

Dec. 31, 2020

ASSET RETIREMENT OBLIGATIONS [Abstract]

Asset Retirement Obligations Operating Costs

in thousands	2020	2019	2018
ARO Operating Costs
Accretion	$        12,432	$        10,992	$       10,776
Depreciation	8,592	7,075	6,034
Total	$        21,024	$        18,067	$       16,810

Reconciliations of Asset Retirement Obligations

in thousands	2020	2019
Asset Retirement Obligations
Balance at beginning of year	$      210,323	$      225,726
Liabilities incurred	353	263
Liabilities settled	(12,820)	(12,457)
Accretion expense	12,432	10,992
Revisions, net	72,875	(14,201)
Balance at end of year	$      283,163	$      210,323