ASSET RETIREMENT OBLIGATIONS (Tables)

6 Months Ended

Jun. 30, 2016

ASSET RETIREMENT OBLIGATIONS [Abstract]

Asset Retirement Obligations Operating Costs

	Three Months Ended		Six Months Ended
	June 30		June 30
in thousands	2016	2015	2016	2015
ARO Operating Costs
Accretion	$        2,716	$        2,936	$        5,472	$        5,787
Depreciation	1,621	1,568	3,314	3,001
Total	$        4,337	$        4,504	$        8,786	$        8,788

Reconciliations of Asset Retirement Obligations

	Three Months Ended		Six Months Ended
	June 30		June 30
in thousands	2016	2015	2016	2015
Asset Retirement Obligations
Balance at beginning of period	$     220,581	$     238,689	$     226,594	$     226,565
Liabilities incurred	505	4,339	505	6,159
Liabilities settled	(5,450)	(1,270)	(10,320)	(8,000)
Accretion expense	2,716	2,936	5,472	5,787
Revisions, net	(1,309)	(9,775)	(5,208)	4,408
Balance at end of period	$     217,043	$     234,919	$     217,043	$     234,919