Stock-Based Compensation - Option Activity (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	9 Months Ended
	Sep. 30, 2013
Number of Options
Outstanding at December 31, 2012	1,412
Granted	201
Exercised	(499)
Forfeited/cancelled/expired	(7)
Outstanding at September 30, 2013	1,107
Vested and expected to vest at September 30, 2013	1,103
Exercisable on September 30, 2013	811
Weighted-Average Exercise Price
Outstanding at December 31, 2012	$ 20.56
Granted	$ 19.68
Exercised	$ 17.00
Forfeited/cancelled/expired	$ 28.08
Outstanding at September 30, 2013	$ 21.96
Vested and expected to vest at September 30, 2013	$ 21.96
Exercisable on September 30, 2013	$ 22.39
Weighted-Average Remaining Contractual Term and Aggregate Intrinsic Value
Outstanding at September 30, 2013	5 years 11 months 12 days
Vested and expected to vest at September 30, 2013	5 years 11 months 8 days
Exercisable on September 30, 2013	4 years 11 months 5 days
Exercised	$ 5,564
Outstanding at September 30, 2013	15,584	[1]
Vested and expected to vest at September 30, 2013	15,519	[1]
Exercisable on September 30, 2013	$ 11,068	[1]

[1] The aggregate intrinsic value represents the total pre-tax value (the difference between our closing stock price on the last trading day of the third quarter of 2013 and the exercise price, multiplied by the number of in-the-money options) that would have been received by the option holders had they all exercised their options on September 30, 2013. This amount will change based on the fair market value of our stock.