REVENUE AND CONTRACT COSTS (Details) $ in Millions	12 Months Ended
Jun. 30, 2019 USD ($) segment	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)
Disaggregation of Revenue [Line Items]
Number of segments \| segment	4
Fiber Solutions [Member]
Disaggregation of Revenue [Line Items]
Revenue from non-lease arrangement	$ 46.5	$ 29.6	$ 34.5
zColo [Member]
Disaggregation of Revenue [Line Items]
Revenue from non-lease arrangement	$ 38.5	$ 39.6	$ 36.9

Amount, including tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value-added and excise.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130539-203045

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130545-203045

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130543-203045

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