LEASES - TWO CREEKS SOLAR PROJECT (Details) $ in Millions	Sep. 30, 2019 USD ($) a extension
Lessee, Lease, Description [Line Items]
Finance lease obligation	$ 48.4
Two Creeks Solar Project
Lessee, Lease, Description [Line Items]
Solar land lease acreage | a	600
Lease initial term	30 years
Number of contract extensions | extension	2
Renewal term	10 years
Lease extended term	50 years
Finance lease obligation	$ 7.7
Finance lease obligation at end of life of solar land contract	$ 0.0