Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2013

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Schedule of Stock Option Activity

The following table presents a summary of option activity and data under the Company’s stock incentive plans as of December 31, 2013:

	Number of Shares		Weighted-Average Exercise Price Per Share		Weighted- Average Remaining Contractual Term	Aggregate Intrinsic Value
Outstanding, January 1, 2011	8,025,411		19.63
Granted	2,108,510		9.01
Exercised	(451,600	)	5.77
Forfeited and expired	(545,644	)	20.31
Outstanding, December 31, 2011	9,136,677		18.51
Granted	1,619,702		17.04
Exercised	(1,342,739	)	11.04
Forfeited and expired	(301,608	)	17.3
Outstanding, December 31, 2012	9,112,032		$	18.61
Granted	2,263,649		32.2
Exercised	(3,425,586	)	20.79
Forfeited and expired	(333,691	)	23.29
Outstanding, December 31, 2013	7,616,404		$	22.83	6.72	$	120,239,781
Vested and expected to vest, December 31, 2013	7,351,832		$	22.59	6.64	$	117,845,281
Exercisable, December 31, 2013	4,280,447		$	19.26	5.18	$	82,884,158
Available for future grant at December 31, 2013	3,432,083

Schedule of Valuation Assumptions

The Company estimated the fair value of each option on the date of grant using the Black-Scholes closed-form option-pricing model applying the weighted average assumptions in the following table.

	Years Ended December 31,
	2013		2012		2011
Expected dividend yield	—	%	—	%	—	%
Expected stock price volatility	48.3	%	46.5	%	49	%
Risk-free interest rate	1.079	%	0.825	%	1.73	%
Expected option term (years)	5.07		4.95		4.75

Schedule of Restricted Stock and Restricted Stock Units Activity

The following table presents a summary of the Company’s outstanding shares of restricted stock awards granted as of December 31, 2013:

	Number of Shares		Weighted Average Grant-Date Fair Value
Outstanding, January 1, 2011	378,128		$	12.18
Awarded	250,224		17.59
Vested	(168,443	)	13.43
Forfeited	(10,648	)	13.42
Outstanding, December 31, 2011	449,261		14.70
Awarded	369,158		21.89
Vested	(188,541	)	15.03
Forfeited	(16,767	)	14.49
Outstanding, December 31, 2012	613,111		18.93
Awarded	266,388		31.8
Vested	(247,945	)	17.61
Forfeited	(28,975	)	22.88
Outstanding, December 31, 2013	602,579		$	24.97

Restricted Stock and ESPP [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Schedule of Valuation Assumptions

	Years Ended December 31,
	2013		2012		2011
Expected dividend yield	—	%	—	%	—	%
Expected stock price volatility	32.46	%	32.65	%	38	%
Risk-free interest rate	0.09	%	0.14	%	0.1	%
Expected option term (years)	0.5		0.5		0.5