ASSET RETIREMENT OBLIGATIONS (Tables)

12 Months Ended

Dec. 31, 2016

ASSET RETIREMENT OBLIGATIONS [Abstract]

Asset Retirement Obligations Operating Costs

in thousands	2016	2015	2014
ARO Operating Costs
Accretion	$        11,059	$        11,474	$       11,601
Depreciation	6,353	6,515	4,462
Total	$        17,412	$        17,989	$       16,063

Reconciliations of Asset Retirement Obligations

in thousands	2016	2015
Asset Retirement Obligations
Balance at beginning of year	$      226,594	$      226,565
Liabilities incurred	505	6,235
Liabilities settled	(17,114)	(18,048)
Accretion expense	11,059	11,474
Revisions, net	2,828	368
Balance at end of year	$      223,872	$      226,594