STOCK-BASED EMPLOYEE COMPENSATION (Tables)

3 Months Ended

Mar. 31, 2017

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Activity of unvested restricted stock units and performance share units

Restricted Stock Units and Performance Share Units

The following table summarizes the activity of restricted stock units and performance share units ("share-based awards") during the three months ended March 31, 2017: 

Share-Based Awards	Shares		Weighted-Average Grant Date Fair Value
Unvested at December 31, 2016	515,606			$	1,287.88
Granted	155,095			$	1,735.10
Vested	(112,791	)		$	1,325.40
Performance Share Units Adjustment	(445	)		$	1,291.76
Forfeited	(7,103	)		$	1,301.58
Unvested at March 31, 2017	550,362			$	1,406.29

Schedule of share-based compensation, stock options, activity

Stock Options

All outstanding employee stock options were assumed in acquisitions. The following table summarizes the activity for stock options during the three months ended March 31, 2017: 

Employee Stock Options	Number of Shares		Weighted-Average Exercise Price			Aggregate  Intrinsic Value (in thousands)			Weighted-Average Remaining Contractual Term (in years)
Balance, December 31, 2016	48,983			$	372.07		$	53,587	4.4
Exercised	(3,992	)		$	368.68
Forfeited	(610	)		$	894.15
Balance, March 31, 2017	44,381			$	365.20		$	62,789	4.2
Vested and exercisable as of March 31, 2017	43,125			$	354.23		$	61,485	4.1
Vested and exercisable as of March 31, 2017 and expected to vest thereafter, net of estimated forfeitures	44,381			$	365.20		$	62,789	4.2