Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2013

Stock-Based Compensation

Summary of stock option activity

Presented below is a summary of our stock option activity for the nine months ended September 30, 2013 (shares in thousands):

	Shares		Weighted Average Exercise Price		Weighted Average Remaining Contractual Terms	Aggregate Intrinsic Value
Outstanding at December 31, 2012	4,757		$	14.11
Granted	3		$	28.74
Exercised	(882	)	$	8.37
Forfeited	(241	)	$	21.36
Expired	(4	)	$	22.27
Outstanding at September 30, 2013	3,633		$	15.05	4.08	$	30,956
Expected to vest at September 30, 2013	1,245		$	24.04	5.71	$	2,873
Exercisable at September 30, 2013	2,199		$	9.17	3.00	$	28,004

Schedule of assumptions used for estimating fair value of options granted

	Nine months ended September 30,
	2013		2012
Expected dividend yield	—		—
Risk-free interest rate	0.67	%	0.70	%
Expected volatility	40.05	%	41.35	%
Expected life	4.47 years		4.47 years

Summary of status of restricted stock units

A summary of the status of our restricted stock units and of changes in restricted stock units outstanding under the 2006 Stock Plan, as amended, for the nine months ended September 30, 2013 is as follows (in thousands, except for weighted average grant date fair value per unit):

	Number of Units		Weighted Average Grant Date Fair Value per Unit		Aggregate Intrinsic Value
Outstanding balance at December 31, 2012	446		$	25.44
Granted	221		$	28.49
Vesting of restricted stock units, net of shares withheld for taxes	(41	)	$	25.05
Shares withheld for taxes	(20	)	$	25.05
Forfeitures	(52	)	$	25.65
Outstanding balance at September 30, 2013	554		$	26.80	$	11,896

Summary of status of restricted stock awards

A summary of the status of our restricted stock awards at September 30, 2013 and of changes in restricted stock awards outstanding under the 2006 Stock Plan for the nine months ended September 30, 2013 is as follows (in thousands, except for weighted average grant date fair value):

	Shares		Weighted Average Grant Date Fair Value per Share		Aggregate Intrinsic Value
Outstanding balance at December 31, 2012	192		$	10.42
Granted	—		—
Vesting of restricted stock awards	(61	)	$	10.42
Shares withheld for payment of taxes upon vesting of restricted stock awards	(35	)	$	10.42
Forfeitures	(14	)	$	10.42
Outstanding balance at September 30, 2013	82		$	10.42	$	1,752