REVENUE RECOGNITION - Contract Balances (Details) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2018	Jun. 30, 2018	Apr. 01, 2018	Mar. 31, 2018
ASSETS:
Customer accounts receivable		$ 155,613	$ 205,299
Increase (decrease) in customer accounts receivable	$ (49,686)
Unbilled receivables		5,190	4,338
Increase (decrease) of unbilled receivables	852
Other receivables		4,528	4,996
Increase (decrease) in other receivables	(468)
Long-term unbilled receivables		4,504	2,254
Increase (decrease) of long-term unbilled receivables	2,250
Contract sssets		169,835	216,887
Increase (decrease) in contract assets	(47,052)
LIABILITIES:
Deferred revenue		248,165	271,698	$ 301,925
Increase (decrease) in deferred revenue	(23,533)
Deferred revenue, long-term		80,491	90,157	$ 91,409
Increase (decrease) in deferred revenue, long-term	(9,666)
Contract liabilities	328,656	$ 328,656	$ 361,855
Increase (decrease) in contract liabilities	(33,199)
Changes In Contract With Customer, Liabilities [Roll Forward]
Revenue recognized in the period	(185,501)
Additions to customer deposits and contract liabilities	152,472
Reclassifications and other adjustments	(170)
Balance at June 30, 2018	$ 328,656