REVENUES - Narrative (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Jan. 01, 2018
Revenue from Contract with Customer [Abstract]
Current contract liabilities	$ 116.9	$ 116.9	$ 99.4	$ 100.6
Noncurrent contract liabilities	8.3	8.3	$ 8.1	$ 6.0
Deferred revenue recognized	$ 37.0	$ 69.9
Capitalized Contract Cost [Line Items]
Amortization period of capitalized contract costs	7 years	7 years
Amortization of capitalized contract costs	$ 13.6	$ 23.8
Obtain Contract
Capitalized Contract Cost [Line Items]
Capitalized contract costs	172.2	172.2
Fulfill Contract
Capitalized Contract Cost [Line Items]
Capitalized contract costs	$ 8.3	$ 8.3

Amount of amortization expense for asset recognized from cost incurred to obtain or fulfill contract with customer.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 340
-SubTopic 40
-Section 50
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Amortization period of cost capitalized in obtaining or fulfilling contract with customer, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

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Amount, after accumulated amortization and accumulated impairment loss, of asset recognized from cost incurred to obtain or fulfill contract with customer; classified as noncurrent.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
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-SubTopic 40
-Section 50
-Paragraph 3
-Subparagraph (a)
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Amount of obligation to transfer good or service to customer for which consideration has been received or is receivable, classified as current.

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Amount of obligation to transfer good or service to customer for which consideration has been received or is receivable, classified as noncurrent.

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Amount of revenue recognized that was previously included in balance of obligation to transfer good or service to customer for which consideration from customer has been received or is due.

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