Stock-Based Compensation (Stock Options Activity) (Details) (Stock Options [Member], Common Stock [Member], USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011
Stock Options [Member] | Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding — January 1	5,556,534		5,914,884
Granted	756,289		1,264,333
Exercised	(1,167,715)		(1,393,794)
Forfeited	(188,378)		(228,889)
Expired	0		0
Outstanding — December 31	4,956,730		5,556,534
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Outstanding — January 1	$ 4.89		$ 3.91
Granted	$ 13.31		$ 8.38
Exercised	$ 4.28		$ 3.84
Forfeited	$ 8.32		$ 5.29
Expired	$ 0.00		$ 0.00
Outstanding — December 31	$ 6.21		$ 4.89
Outstanding, Weighted Average Remaining Contractual Term	6 years 10 months 24 days
Outstanding, Aggregate Intrinsic Value	$ 39,947	[1]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Total Intrinsic Value	11	[2]	7	[2]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Vested and Expected to Vest, December 31, 2012 Number of Stock Options (Shares)	4,235,058
Vested and Expected to Vest, December 31, 2012 Outstanding, Weighted Average Exercise Price	$ 5.87
Vested and Expected to Vest, December 31, 2012 Weighted Average Remaining Contractual Term	6 years 8 months 12 days
Vested and Expected to Vest, December 31, 2012 Aggregate Intrinsic Value	35,536	[1]
Vested December 31, 2012 Number of Stock Options (Shares)	2,551,156
Vested, December 31, 2012 Weighted Average Exercise Price	$ 4.35
Vested, December 31, 2012 Weighted Average Remaining Contractual Term	5 years 8 months 12 days
Vested, December 31, 2012 Aggregate Intrinsic Value	$ 25,242	[1]

[1] Represents the total difference between the Company's closing stock price on the last trading day of 2012 and the stock option exercise price, multiplied by the number of in-the-money options as of December 31, 2012. The amount of intrinsic value will change based on the fair market value of the Company's stock.

[2] Represents the total difference between the Company's stock price at the time of exercise and the stock option exercise price, multiplied by the number of options exercised.