Stock-Based Compensation (Additional Information) (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Expected dividend yield (percent)				0.00%
Compensation expense (income)			$ 3,704,000	$ 3,775,000
Options exercised, total intrinsic value			11,700,000
Total amount of cash received from exercise of options			26,000,000
Employee stock purchase plan, number of offering (offering period)			2
Employee stock purchase plan, offering period (months)			6 months
Employee Stock Purchase Plan [Member]
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Compensation expense (income)	100,000	100,000	300,000	300,000
Employee stock purchase plan, purchase price discount (percent)			15.00%
Stock Options [Member]
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Stock options, contractual term (years)			10 years
Expected dividend yield (percent)			0.00%
Stock-based compensation, approximate forfeitures rate (percent)			3.00%
Compensation expense (income)	300,000	400,000	300,000	1,700,000
Performance-Based Restricted Stock [Member]
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Expected dividend yield (percent)	0.00%
Compensation expense (income)	500,000	200,000	600,000	200,000
Restricted stock award program, measurement period (years)			3 years
Restricted stock award program, payment of award as percentage of target (percent)					200.00%
Performance-Based Restricted Stock [Member] | Minimum [Member]
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Restricted stock award program, awarded shares as a percentage of the original award amount (percent)			0.00%
Performance-Based Restricted Stock [Member] | Maximum [Member]
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Restricted stock award program, awarded shares as a percentage of the original award amount (percent)			200.00%
Time Based Restricted Stock [Member]
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Compensation expense (income)	1,200,000	400,000	1,800,000	1,200,000
Restricted stock award program, vesting period (years)			3 years
Deferred Stock Units [Member]
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Compensation expense (income)	0	0	700,000	700,000
Employee Severance [Member] | Stock Options [Member]
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Compensation expense (income)	700,000
Modification of Stock Option Grant [Member] | Employee Severance [Member] | Stock Options [Member]
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Compensation expense (income)	$ 200,000