ASSET RETIREMENT OBLIGATIONS (Tables)

12 Months Ended

Dec. 31, 2018

ASSET RETIREMENT OBLIGATIONS [Abstract]

Asset Retirement Obligations Operating Costs

in thousands	2018	2017	2016
ARO Operating Costs
Accretion	$        10,776	$        11,415	$       11,059
Depreciation	6,034	6,302	6,353
Total	$        16,810	$        17,717	$       17,412

Reconciliations of Asset Retirement Obligations

in thousands	2018	2017
Asset Retirement Obligations
Balance at beginning of year	$      218,117	$      223,872
Liabilities incurred	20	1,920
Liabilities settled	(13,558)	(21,477)
Accretion expense	10,776	11,415
Revisions, net	10,371	2,387
Balance at end of year	$      225,726	$      218,117