COMMITMENTS AND CONTINGENCIES (Details) - USD ($) $ in Millions	1 Months Ended
Jan. 31, 2018	Dec. 31, 2018
COMMITMENTS AND CONTINGENCIES
Purchase orders outstanding for equipment, parts and supplies		$ 90.2
Contingencies
Contingent gains recognized in consolidated financial statements		$ 0.0
Litigation settlement	$ 21.0

Amount of gain recognized in the period that had been disclosed in prior periods as a contingent gain.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 30
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6397426&loc=d3e17499-108355

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant