SEGMENT AND GEOGRAPHIC INFORMATION - REVENUE BY GEOGRAPHIC REGION (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Net revenue by geographic region:
Total net revenue	$ 450,274	$ 480,840	$ 443,562	$ 418,216	$ 571,555	$ 476,474	$ 420,167	$ 311,552	$ 1,792,892	$ 1,779,748	$ 1,413,698
United States
Net revenue by geographic region:
Total net revenue									1,052,313	999,128	742,963
Europe
Net revenue by geographic region:
Total net revenue									531,514	515,696	449,577
Asia Pacific
Net revenue by geographic region:
Total net revenue									111,223	157,183	120,629
Canada and Latin America
Net revenue by geographic region:
Total net revenue									$ 97,842	$ 107,741	$ 100,529