SEGMENT REPORTING (Narrative) (Details)	Sep. 30, 2019
Fiber Solutions [Member] | Minimum
Segment Reporting Information [Line Items]
Contract term	3 years
Fiber Solutions [Member] | Maximum
Segment Reporting Information [Line Items]
Contract term	20 years
Layer 2/3 [Member] | Minimum
Segment Reporting Information [Line Items]
Contract term	1 year
Layer 2/3 [Member] | Maximum
Segment Reporting Information [Line Items]
Contract term	5 years
Transport [Member] | Minimum
Segment Reporting Information [Line Items]
Contract term	2 years
Transport [Member] | Maximum
Segment Reporting Information [Line Items]
Contract term	5 years
zColo [Member] | Minimum
Segment Reporting Information [Line Items]
Contract term	2 years
zColo [Member] | Maximum
Segment Reporting Information [Line Items]
Contract term	5 years
Other [Member]
Segment Reporting Information [Line Items]
Contract term	1 year