SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details)	3 Months Ended
	Mar. 31, 2019 USD ($)	Mar. 31, 2018 USD ($)	Jan. 01, 2019 USD ($)
Significant Accounting Policies [Line Items]
Number of natural gas distribution services customers	2,200,000
Segment Reporting, Disclosure of Major Customers	0	0
Capital Expenditures Incurred but Not yet Paid	$ 1,700,000	$ 9,700,000
Operating Lease, Right-of-Use Asset	38,500,000		$ 32,000,000
Operating Lease, Liability	$ 38,500,000		$ 32,000,000