Employee Stock Compensation

6 Months Ended

Jun. 30, 2016

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Employee Stock Compensation

2. Employee Stock Compensation

The Company granted the following number of share-based awards:

	Three Months Ended June 30,				Six Months Ended June 30,
	2016		2015		2016		2015
Stock options		39,400		53,200		783,700		976,900
Stock appreciation rights	—		—			25,200		176,200
Restricted stock units		84,065		10,389		373,836		237,210
Performance units	—		—			119,839		51,977

The Company had the following number of share-based awards outstanding:

	June 30, 2016		December 31, 2015
Stock options		6,794,700		6,647,999
Stock appreciation rights		530,476		530,701
Restricted stock units		664,709		359,553
Performance units		164,886		49,667

The Company used the following assumptions when estimating the value of the share-based compensation for stock options and stock appreciation rights issued as follows:

	Three Months Ended June 30,				Six Months Ended June 30,
	2016		2015		2016		2015
Expected volatility	26 – 29%		28 – 37%		26 – 30%		28 – 41%
Weighted average expected volatility		26%		31%		28%		35%
Expected dividends		0.0%		0.0%		0.0%		0.0%
Expected term (in years)	3.6 – 6.6		3.7 – 6.7		3.6 – 6.6		3.7 – 6.7
Risk-free interest rate	0.80 – 1.23%		1.16 – 2.00%		0.80 – 1.57%		1.06 – 2.00%

The Company issued 52,772 shares and 38,449 shares of common stock for purchases under its employee stock purchase plan during the six months ended June 30, 2016 and 2015, respectively.

The Company recognized share-based compensation expense of $10.1 million and $10.7 million during the three months ended June 30, 2016 and 2015, respectively, and $18.8 million and $20.3 million during the six months ended June 30, 2016 and 2015, respectively.