Share Based Compensation

6 Months Ended

Jun. 30, 2015

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

Share Based Compensation

4. Share Based Compensation

The Company has Stock Incentive Plans (the Plans) pursuant to which the Company’s board of directors may grant stock options or restricted stock to employees. The table below summarizes the expense recognized related to share-based payments recognized for the three and six month periods ended June 30 (in thousands):

	Three Months Ended June 30,				Six Months Ended June 30,
	2015		2014		2015		2014
Stock options	$	4,484	$	2,889	$	8,842	$	6,300
Restricted stock		9,065		4,798		21,658		11,999
Stock-based compensation	$	13,549	$	7,687	$	30,500	$	18,299

The tax benefits recorded on stock based compensation were $10.8 million and $6.2 million for the six month periods ended June 30, 2015 and 2014, respectively.

The following table summarizes the Company’s total unrecognized compensation cost related to stock-based compensation as of June 30, 2015 (in thousands):

	Unrecognized Compensation Cost		Weighted Average Period of Expense Recognition (in Years)
Stock options	$	71,153		1.80
Restricted stock		19,811		1.29
Total	$	90,964

Stock Options

Stock options are granted with an exercise price estimated to be equal to the fair market value on the date of grant as authorized by the Company’s board of directors. Options granted have vesting provisions ranging from one to six years. Certain stock option awards also have performance vesting provisions. Stock option grants are generally subject to forfeiture if employment terminates prior to vesting.

The following summarizes the changes in the number of shares of common stock under option for the six month period ended June 30, 2015 (shares and aggregate intrinsic value in thousands):

	Shares			Weighted Average Exercise Price		Options Exercisable at End of Period		Weighted Average Exercise Price of Exercisable Options		Weighted Average Fair Value of Options Granted During the Period		Aggregate Intrinsic Value
Outstanding at December 31, 2014		5,131		$	58.71		2,370	$	21.75			$	461,770
Granted		271			155.95					$	38.07
Exercised		(209	)		33.90								25,541
Forfeited		(25	)		105.36
Outstanding at June 30, 2015		5,168		$	64.60		2,476	$	23.68			$	472,719
Expected to vest as of June 30, 2015		5,168		$	64.60

The aggregate intrinsic value of stock options exercisable at June 30, 2015 was $327.8 million. The weighted average contractual term of options exercisable at June 30, 2015 was 5.4 years.

The fair value of stock option awards granted was estimated using the Black-Scholes option pricing model during the six months ended June 30, 2015 and 2014, with the following weighted-average assumptions for grants during the period.

	June 30
	2015			2014
Risk-free interest rate		1.28	%		0.90	%
Dividend yield		—			—
Expected volatility		28.47	%		34.92	%
Expected life (in years)		4.0			3.8

Restricted Stock

Awards of restricted stock and restricted stock units are independent of stock option grants and are generally subject to forfeiture if employment terminates prior to vesting. The vesting of the restricted stock and restricted stock units granted is generally based on the passage of time, performance or market conditions. Shares vesting based on the passage of time have vesting provisions ranging from one to four years.

The following table summarizes the changes in the number of shares of restricted stock and restricted stock units for the six months ended June 30, 2015 (shares in thousands):

	Shares			Weighted Average Grant Date Fair Value
Unvested at December 31, 2014		716		$	121.38
Granted		89			155.65
Vested		(100	)		123.33
Cancelled		(5	)		35.78
Unvested at June 30, 2015		700		$	126.67