ASSET RETIREMENT OBLIGATIONS (Tables)

9 Months Ended

Sep. 30, 2017

ASSET RETIREMENT OBLIGATIONS [Abstract]

Asset Retirement Obligations Operating Costs

	Three Months Ended		Nine Months Ended
	September 30		September 30
in thousands	2017	2016	2017	2016
ARO Operating Costs
Accretion	$        2,857	$        2,692	$        8,620	$        8,163
Depreciation	1,494	1,469	4,741	4,783
Total	$        4,351	$        4,161	$      13,361	$      12,946

Reconciliations of Asset Retirement Obligations

	Three Months Ended		Nine Months Ended
	September 30		September 30
in thousands	2017	2016	2017	2016
Asset Retirement Obligations
Balance at beginning of period	$     223,953	$     217,043	$     223,872	$     226,594
Liabilities incurred	731	0	1,066	505
Liabilities settled	(5,263)	(3,937)	(15,739)	(14,256)
Accretion expense	2,857	2,692	8,620	8,163
Revisions, net	610	(1,112)	5,069	(6,320)
Balance at end of period	$     222,888	$     214,686	$     222,888	$     214,686