Share Based Compensation (Tables)

3 Months Ended

Mar. 31, 2015

Summary of Expense Related to Share-Based Payments

The table below summarizes the expense recognized related to share-based payments recognized for the three month periods ended March 31 (in thousands):

	Three Months Ended March 31,
	2015		2014
Stock options	$	4,358	$	3,412
Restricted stock		12,593		7,200
Stock-based compensation	$	16,951	$	10,612

Summary of Total Unrecognized Compensation Cost Related to Stock-Based Compensation

The following table summarizes the Company’s total unrecognized compensation cost related to stock-based compensation as of March 31, 2015 (in thousands):

	Unrecognized Compensation Cost		Weighted Average Period of Expense Recognition (in Years)
Stock options	$	74,540		2.00
Restricted stock		38,965		1.25
Total	$	113,505

Summary of Changes in Number of Shares of Common Stock Under Option

The following summarizes the changes in the number of shares of common stock under option for the three month period ended March 31, 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		241			155.65					$	38.12
Exercised		(109	)		23.49								13,850
Forfeited		(25	)		105.36
Outstanding at March 31, 2015		5,238		$	63.68		2,290	$	22.40			$	456,995
Expected to vest as of March 31, 2015		5,238		$	63.68

Summary of Changes in Number of Shares of Restricted Stock and Restricted Stock Units

The following table summarizes the changes in the number of shares of restricted stock and restricted stock units for the three months ended March 31, 2015 (shares in thousands):

	Shares			Weighted Average Grant Date Fair Value
Unvested at December 31, 2014		716		$	121.38
Granted		89			155.65
Vested		(39	)		100.52
Cancelled		(5	)		35.78
Unvested at March 31, 2015		761		$	127.55

Stock Options [Member]

Schedule of Weighted-Average Assumptions

The fair value of stock option awards granted was estimated using the Black-Scholes option pricing model during the three months ended March 31, 2015 and 2014, with the following weighted-average assumptions for grants during the period.

	March 31
	2015			2014
Risk-free interest rate		1.29	%		0.95	%
Dividend yield		—			—
Expected volatility		28.51	%		34.91	%
Expected life (in years)		4.0			4.0