DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES - Changes in Value Recognized in OCI (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Losses reclassified from AOCI to income
Gain (Loss) Recognized in OCI on Derivatives	$ 2,033	$ 7,129	$ 1,311	$ 30,203
Loss Reclassified from AOCI to Income (Effective Portion)	(2,296)	(2,296)	(6,888)	(6,928)
Cash Flow Hedge
Losses reclassified from AOCI to income
Gain (Loss) Recognized in OCI on Derivatives	2,033	7,129	1,311	30,203
Loss Reclassified from AOCI to Income (Effective Portion)	(2,296)	(6,928)	(6,888)	(2,296)
Cash Flow Hedge \| Interest rate derivative contracts
Losses reclassified from AOCI to income
Gain (Loss) Recognized in OCI on Derivatives	0	7,322	0	27,739
Cash Flow Hedge \| Commodity derivatives
Losses reclassified from AOCI to income
Gain (Loss) Recognized in OCI on Derivatives	2,033	(193)	1,311	2,464
Interest and debt expense \| Cash Flow Hedge \| Interest rate derivative contracts
Losses reclassified from AOCI to income
Loss Reclassified from AOCI to Income (Effective Portion)	$ (2,296)	$ (6,928)	$ (6,888)	$ (2,296)

Amount, after tax and reclassification, of gain (loss) from derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness, attributable to parent.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=118930883&loc=d3e637-108580

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Amount, after tax, of reclassification of gain (loss) from accumulated other comprehensive income (AOCI) for derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=118930883&loc=d3e689-108580

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=118930883&loc=d3e637-108580

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