STOCK BASED COMPENSATION (Tables)

6 Months Ended

Jun. 30, 2016

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock-Based Compensation Expense Resulting from Stock Option Awards, Restricted stock units ("RSU") and ESPP

The following table presents the total stock-based compensation expense resulting from stock option awards, restricted stock units (“RSUs”), and the ESPP included in the Condensed Consolidated Statements of Income:

In thousands
	Three Months Ended June 30,				Six Months Ended June 30,
	2016		2015		2016		2015
Cost of revenues – stock option plan	$	12	$	22	$	27	$	45
Selling, general and administrative – stock option plan		4,585		4,650		9,337		9,379
Selling, general and administrative – RSUs		399		375		958		721
Selling, general and administrative – ESPP		456		370		1,235		759
Total pre-tax expense	$	5,452	$	5,417	$	11,557	$	10,904

Stock Option Activity

Stock option activity for the six months ended June 30, 2016 is summarized as follows:

	Number of Options			Weighted Average Exercise Price per Share		Weighted Average Remaining Contractual Life		Total Aggregate Intrinsic Value
						(in years)		(in thousands)
Outstanding at beginning of year		5,334,803		$	92.02
Granted		1,040,107			110.93
Exercised		(437,584	)		70.20
Forfeited		(186,507	)		116.07
Canceled or expired		(7,950	)		102.64
Outstanding at June 30, 2016		5,742,869			96.32		5.68	$	85,756
Exercisable at June 30, 2016		3,153,185			82.22		4.75	$	80,141

Intrinsic Value of Options Exercised

The following table sets forth the total intrinsic value of options exercised:

	Three Months Ended June 30,				Six Months Ended June 30,
	2016		2015		2016		2015
Total intrinsic value of options exercised	$	7,021	$	10,125		20,250		39,650

Assumptions used in Black-Scholes Model

The estimated fair value of stock options at the time of the grant using the Black-Scholes option pricing model was as follows:

	Three Months Ended June 30,						Six Months Ended June 30,
	2016			2015			2016			2015
Stock options granted (shares)		31,538			74,742			1,040,107			935,276
Weighted average fair value at grant date (per share)	$	19.69		$	22.18		$	20.17		$	22.80
Assumptions:
Expected term (in years)		4.80			4.79			4.77			4.79
Expected volatility		20.96	%		15.98	%		18.11	%		16.58	%
Expected dividend yield		—	%		—	%		—	%		—	%
Risk free interest rate		1.26	%		1.43	%		1.22	%		1.44	%

Restricted Stock Units Activity

A summary of the status of our non-vested RSUs and changes during the six months ended June 30, 2016 are as follows:

	Number of Options			Weighted Average Grant Date Fair Value		Weighted Average Remaining Contractual Life		Total Aggregate Intrinsic Value
						(in years)		(in thousands)
Non-vested at beginning of year		71,451		$	101.29
Granted		59,072			109.99
Forfeited		(17,850	)		105.38
Non-vested at June 30, 2016		112,673			105.21		2.92	$	11,732