Stock-Based Compensation (Details 2) (Stock Option, USD $)	12 Months Ended
	Dec. 31, 2014
Information of stock options by exercise price range.
Number Outstanding (in shares)	4,464,021
Outstanding Weighted-Average Exercise Price (in dollars per share)	$ 11.50
Outstanding Weighted-Average Remaining Life	5 years 4 months 2 days
Number Exercisable (in shares)	2,137,350
Exercisable Weighted-Average Exercise Price (in dollars per share)	$ 15.10
$ 0.00 - 6.99
Information of stock options by exercise price range.
Range of Exercise Prices, minimum (in dollars per share)	$ 0.00
Range of Exercise Prices, maximum (in dollars per share)	$ 6.99
Number Outstanding (in shares)	656,710
Outstanding Weighted-Average Exercise Price (in dollars per share)	$ 6.13
Outstanding Weighted-Average Remaining Life	2 years 10 months 24 days
Number Exercisable (in shares)	266,500
Exercisable Weighted-Average Exercise Price (in dollars per share)	$ 6.04
$ 7.00 - 10.99
Information of stock options by exercise price range.
Range of Exercise Prices, minimum (in dollars per share)	$ 7.00
Range of Exercise Prices, maximum (in dollars per share)	$ 10.99
Number Outstanding (in shares)	2,269,986
Outstanding Weighted-Average Exercise Price (in dollars per share)	$ 8.40
Outstanding Weighted-Average Remaining Life	7 years 8 months 5 days
Number Exercisable (in shares)	468,650
Exercisable Weighted-Average Exercise Price (in dollars per share)	$ 8.70
$ 11.00 - 11.99
Information of stock options by exercise price range.
Range of Exercise Prices, minimum (in dollars per share)	$ 11.00
Range of Exercise Prices, maximum (in dollars per share)	$ 11.99
Number Outstanding (in shares)	469,875
Outstanding Weighted-Average Exercise Price (in dollars per share)	$ 11.90
Outstanding Weighted-Average Remaining Life	4 years 10 months 13 days
Number Exercisable (in shares)	377,125
Exercisable Weighted-Average Exercise Price (in dollars per share)	$ 11.90
$ 12.00 - 15.99
Information of stock options by exercise price range.
Range of Exercise Prices, minimum (in dollars per share)	$ 12.00
Range of Exercise Prices, maximum (in dollars per share)	$ 15.99
Number Outstanding (in shares)	390,375
Outstanding Weighted-Average Exercise Price (in dollars per share)	$ 14.24
Outstanding Weighted-Average Remaining Life	4 years 2 months 16 days
Number Exercisable (in shares)	348,000
Exercisable Weighted-Average Exercise Price (in dollars per share)	$ 14.45
$ 16.00 - 24.49
Information of stock options by exercise price range.
Range of Exercise Prices, minimum (in dollars per share)	$ 16.00
Range of Exercise Prices, maximum (in dollars per share)	$ 24.49
Number Outstanding (in shares)	53,000
Outstanding Weighted-Average Exercise Price (in dollars per share)	$ 17.66
Outstanding Weighted-Average Remaining Life	2 years 11 months 23 days
Number Exercisable (in shares)	53,000
Exercisable Weighted-Average Exercise Price (in dollars per share)	$ 17.66
$ 24.50 - 28.85
Information of stock options by exercise price range.
Range of Exercise Prices, minimum (in dollars per share)	$ 24.50
Range of Exercise Prices, maximum (in dollars per share)	$ 28.85
Number Outstanding (in shares)	624,075
Outstanding Weighted-Average Exercise Price (in dollars per share)	$ 25.86
Outstanding Weighted-Average Remaining Life	8 months 5 days
Number Exercisable (in shares)	624,075
Exercisable Weighted-Average Exercise Price (in dollars per share)	$ 25.86