STOCK BASED COMPENSATION (Tables)

9 Months Ended

Sep. 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  September 30,				Nine Months Ended  September 30,
	2016		2015		2016		2015
Cost of revenues – stock option plan	$	26	$	24	$	53	$	69
Selling, general and administrative – stock option plan		4,287		4,416		13,624		13,795
Selling, general and administrative – RSUs		302		382		1,260		1,103
Selling, general and administrative – ESPP		499		432		1,734		1,191
Total pre-tax expense	$	5,114	$	5,254	$	16,671	$	16,158

Stock Option Activity

Stock option activity for the nine months ended September 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		1,095,207			110.40
Exercised		(533,142	)		67.39
Forfeited		(233,905	)		115.50
Canceled or expired		(48,254	)		103.57
Outstanding at September 30, 2016		5,614,709		$	96.87		5.53	$	29,630
Exercisable at September 30, 2016		3,024,883		$	82.91		4.63	$	29,630

Intrinsic Value of Options Exercised

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

	Three Months Ended  September 30,				Nine Months Ended  September 30,
	2016		2015		2016		2015
Total intrinsic value of options exercised	$	4,443	$	14,888	$	24,693	$	54,538

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  September 30,						Nine Months Ended  September 30,
	2016			2015			2016			2015
Stock options granted (shares)		55,100			24,275			1,095,207			959,551
Weighted average fair value at grant date (per share)	$	20.02		$	23.88		$	20.17		$	22.83
Assumptions:
Expected term (in years)		4.80			4.79			4.77			4.79
Expected volatility		21.30	%		16.01	%		18.26	%		16.56	%
Expected dividend yield		—	%		—	%		—	%		—	%
Risk free interest rate		0.95	%		1.49	%		1.21	%		1.44	%

Restricted Stock Units Activity

A summary of the status of our non-vested RSUs and changes during the nine months ended September 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		76,712			106.38
Forfeited		(22,788	)		103.25
Non-vested at September 30, 2016		125,375		$	104.05		1.99	$	10,048