STOCK-BASED COMPENSATION (Tables)

6 Months Ended

Jun. 30, 2017

STOCK-BASED COMPENSATION

Schedule of weighted-average assumptions used to estimate the fair value of options granted

	Three-Months Ended June 30,		Six-Months Ended June 30,
	2017	2016	2017	2016
Dividend yield	0.0%	0.0%	0.0%	0.0%
Expected volatility	36.5%	36.2%	36.6%	36.2%
Risk-free interest rate	1.8%	1.3%	2.1%	1.4%
Expected term	6.1 years	6.4 years	6.1 years	6.3 years

Summary of Company's activities with respect to its stock option plans

Options	Number of Shares (In thousands)	Weighted- Average Exercise Price Per Share		Weighted- Average Remaining Contractual Term (In years)	Aggregate Intrinsic Value
Outstanding at January 1, 2017	22,643	$	23.55	5.8	$	474,739
Granted 01/01/17 - 03/31/17	1,319	$	45.94
Granted 04/01/17 - 06/30/17	26	$	49.71
Exercised	(1,278)	$	14.94
Cancelled or forfeited	(299)	$	40.47
Outstanding at June 30, 2017	22,411	$	25.16	5.6	$	549,689
Vested and expected to vest in the future at June 30, 2017	21,157	$	24.12	5.4	$	540,993
Exercisable at June 30, 2017	13,135	$	14.33	3.7	$	464,352

Summary of Company's activities with respect to non-vested restricted stock units

	Number of Shares (in thousands)	Weighted Average Grant-Date Fair Value
Non-vested at January 1, 2017	556	$	39.95
Granted 01/01/17- 03/31/17	252	$	46.27
Granted 04/01/17- 06/30/17	23	$	50.86
Vested	(283)	$	37.95
Forfeited/cancelled	(2)	$	20.69
Non-vested at June 30, 2017	546	$	44.43