STOCK-BASED COMPENSATION - Fair Value Assumptions (Details) - Stock options - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended				12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Weighted-average assumptions used to estimate the fair value of options granted
Dividend yield (as a percent)					0.00%	0.00%	0.00%
Expected volatility (as a percent)					36.20%	37.10%	41.40%
Risk-free interest rate (as a percent)					1.57%	1.57%	1.55%
Expected term					6 years 3 months 18 days	5 years 9 months 18 days	5 years 9 months 18 days
Stock Options, Number of Shares
Balance at the beginning of the period (in shares)				19,770	19,770
Granted (in shares)	1,510	42	657	2,883
Exercised (in shares)					(1,887)
Cancelled or forfeited (in shares)					(332)
Balance at the end of the period (in shares)	22,643				22,643	19,770
Vested and expected to vest in the future at the end of the period (in shares)	21,269				21,269
Exercisable at the end of the period (in shares)	12,231				12,231
Stock options, Weighted-Average Exercise Price Per Share
Balance at the beginning of the period (in dollars per share)				$ 16.95	$ 16.95
Granted (in dollars per share)	$ 43.87	$ 52.60	$ 46.18	$ 44.02
Exercised (in dollars per share)					8.72
Cancelled or forfeited (in dollars per share)					33.65
Balance at the end of the period (in dollars per share)	23.55				23.55	$ 16.95
Vested and expected to vest in the future at the end of the period (in dollars per share)	22.40				22.40
Exercisable at the end of the period (in dollars per share)	$ 11.26				$ 11.26
Weighted-Average Remaining Contractual Term
Balance at the beginning of the period					5 years 9 months 18 days	5 years 7 months 6 days
Balance at the end of the period					5 years 9 months 18 days	5 years 7 months 6 days
Vested and expected to vest in the future at the end of the period					5 years 7 months 6 days
Exercisable at the end of the period					3 years 7 months 6 days
Aggregate Intrinsic Value
Balance at the beginning of the period				$ 646,497	$ 646,497
Balance at the end of the period	$ 474,739				474,739	$ 646,497
Vested and expected to vest in the future at the end of the period	470,017				470,017
Exercisable at the end of the period	$ 404,982				$ 404,982