ASSET RETIREMENT OBLIGATIONS (Tables)

3 Months Ended

Mar. 31, 2017

ASSET RETIREMENT OBLIGATIONS [Abstract]

Asset Retirement Obligations Operating Costs

	Three Months Ended
	March 31
in thousands	2017	2016
ARO Operating Costs
Accretion	$        2,882	$        2,755
Depreciation	1,632	1,693
Total	$        4,514	$        4,448

Reconciliations of Asset Retirement Obligations

	Three Months Ended
	March 31
in thousands	2017	2016
Asset Retirement Obligations
Balance at beginning of year	$     223,872	$     226,594
Liabilities incurred	0	0
Liabilities settled	(4,865)	(4,868)
Accretion expense	2,882	2,755
Revisions, net	4,123	(3,900)
Balance at end of period	$     226,012	$     220,581