ASSET RETIREMENT OBLIGATIONS (Tables)

12 Months Ended

Dec. 31, 2015

ASSET RETIREMENT OBLIGATIONS [Abstract]

Asset Retirement Obligations Operating Costs

in thousands	2015	2014	2013
ARO Operating Costs
Accretion	$        11,474	$        11,601	$       10,685
Depreciation	6,515	4,462	3,527
Total	$        17,989	$        16,063	$       14,212

Reconciliations of Asset Retirement Obligations

in thousands	2015	2014
Asset Retirement Obligations
Balance at beginning of year	$      226,565	$      228,234
Liabilities incurred	6,235	9,130
Liabilities settled	(18,048)	(26,547)
Accretion expense	11,474	11,601
Revisions, net	368	4,147
Balance at end of year	$      226,594	$      226,565