REVENUE RECOGNITION - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2018	Jun. 30, 2018	Jan. 01, 2018	Dec. 31, 2017
Revenue from Contract with Customer [Abstract]
Deferred revenue			$ 377,200	$ 332,200
Deferred revenue recognized during period	$ 220,400	$ 317,200
Deferred revenue	381,397	381,397			$ 342,483
Noncurrent deferred revenue	1,800	1,800
Amortization expense recognized related to contract cost assets	94,400	254,300
Current contract assets	69,900	69,900
Non-current contract assets	$ 5,600	$ 5,600

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

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Amount, after allowance for credit loss, of right to consideration in exchange for good or service transferred to customer when right is conditioned on something other than passage of time, 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.

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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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