ASSET RETIREMENT OBLIGATIONS (Tables)

6 Months Ended

Jun. 30, 2017

ASSET RETIREMENT OBLIGATIONS [Abstract]

Asset Retirement Obligations Operating Costs

	Three Months Ended		Six Months Ended
	June 30		June 30
in thousands	2017	2016	2017	2016
ARO Operating Costs
Accretion	$        2,881	$        2,716	$        5,763	$        5,472
Depreciation	1,615	1,621	3,247	3,314
Total	$        4,496	$        4,337	$        9,010	$        8,786

Reconciliations of Asset Retirement Obligations

	Three Months Ended		Six Months Ended
	June 30		June 30
in thousands	2017	2016	2017	2016
Asset Retirement Obligations
Balance at beginning of period	$     226,012	$     220,581	$     223,872	$     226,594
Liabilities incurred	335	505	335	505
Liabilities settled	(5,610)	(5,450)	(10,475)	(10,320)
Accretion expense	2,881	2,716	5,763	5,472
Revisions, net	335	(1,309)	4,458	(5,208)
Balance at end of period	$     223,953	$     217,043	$     223,953	$     217,043