Share Based Compensation (Tables)

9 Months Ended

Sep. 30, 2012

Summary Of Expense Related To Share-Based Payments

The table below summarizes the expense recognized related to share-based payments recognized for the three and nine month periods ended September 30 (in thousands):

	Three Months  Ended September 30,				Nine Months  Ended September 30,
	2012		2011		2012		2011
Stock options	$	2,836	$	2,032	$	7,462	$	7,086
Restricted stock		3,658		1,607		6,825		8,536
Stock-based compensation	$	6,494	$	3,639	$	14,287	$	15,622

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 September 30, 2012 (in thousands):

	Unrecognized Compensation Cost		Weighted Average Period  of Expense Recognition (in Years)
Stock options	$	30,449		2.34
Restricted stock		7,684		1.21
Total	$	38,133

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 nine month period ended September 30, 2012 (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, 2011		8,341		$	15.51		4,394	$	10.13			$	119,802
Granted		1,158			36.34					$	10.65
Exercised		(2,425	)		8.71								87,521
Forfeited		(44	)		15.54
Outstanding at September 30, 2012		7,031		$	21.22		3,052	$	13.72			$	165,792
Expected to vest as of September 30, 2012		7,031		$	21.22

Schedule Of Weighted-Average Assumptions

The fair value of stock option awards granted was estimated using the Black-Scholes option pricing model during the nine months ended September 30, 2012 and 2011, with the following weighted-average assumptions for grants during the period.

	Nine Months Ended September 30,
	2012			2011
Risk-free interest rate		0.59	%		1.74	%
Dividend yield		—			—
Expected volatility		36.53	%		39.06	%
Expected life (in years)		4.0			4.0

Schedule Of Weighted-Average Assumptions

The fair value of restricted stock awards granted which included market conditions during the nine months ended September 30, 2011 was estimated using the Monte Carlo option pricing model at the grant date, with the following assumptions.

	Nine Months Ended September 30, 2011
Risk-free interest rate		1.25	%
Dividend yield		—
Expected volatility		37.00	%
Expected life (in years)		0.63

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 nine months ended September 30, 2012 (shares in thousands):

	Shares			Weighted Average Grant Date Fair Value
Unvested at December 31, 2011		840		$	23.15
Granted		131			36.27
Vested		(224	)		23.31
Cancelled		(25	)		33.49
Unvested at September 30, 2012		722		$	25.21