INCOME TAXES (Components of Net Deferred Income Tax Liability) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
INCOME TAXES [Abstract]
Employee benefits	$ 78,999	$ 97,757
Asset retirement obligations & other reserves	59,507	53,670
Deferred compensation	117,298	121,900
State net operating losses	61,658	59,315
Federal credit carryforwards	34,340	40,212
Other	48,856	52,241
Total gross deferred tax assets	400,658	425,095
Valuation allowance	(59,323)	(56,867)
Total net deferred tax assets	341,335	368,228
Property, plant and equipment	665,057	661,697
Goodwill/other intangible assets	324,910	329,539
Other	32,464	28,403
Total deferred tax liabilities	1,022,431	1,019,639
Net deferred tax liability	681,096	$ 651,411
Deferred income taxes noncurrent	$ 44,464

Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards.

Name:	us-gaap_DeferredTaxAssetsGross
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount after allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards, net of deferred tax liability attributable to taxable temporary differences.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32537-109319