STOCK-BASED COMPENSATION (Stock Options Activity) (Details) - Employee Stock Option - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2019
Number of Options
Options outstanding at January 1, 2019	4,082,944
Options granted	131,849
Options modified	17,871
Options exercised	(668,339)
Options forfeited/cancelled	(10,701)
Options outstanding at September 30, 2019	3,553,624
Options vested and exercisable at September 30, 2019	3,129,141
Options expected to vest at September 30, 2019	397,070
Weighted Average Exercise Price
Options outstanding at January 1, 2019	$ 44.54
Options granted	169.13
Options modified	163.55
Options exercised	43.09
Options forfeited/cancelled	97.83
Options outstanding at September 30, 2019	49.87
Options vested and exercisable at September 30, 2019	41.01
Options expected to vest at September 30, 2019	$ 114.20
Aggregate Intrinsic Value
Options outstanding at September 30, 2019	$ 470,672
Options vested and exercisable at September 30, 2019	442,179
Options expected to vest at September 30, 2019	$ 27,050
Weighted Average Remaining Contractual Term (in years)
Options outstanding at September 30, 2019	4 years 10 months 24 days
Options vested and exercisable at September 30, 2019	4 years 6 months
Options expected to vest at September 30, 2019	8 years 3 months 18 days