Stock-Based Compensation (Summary of Stock Options Activity) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Number of Shares
Total Granted and Outstanding (in shares)	1,989,000
Stock Options [Member]
Number of Shares
Total Granted and Outstanding, beginning of period (in shares)	1,295,000
Granted (in shares)	714,000
Exercised (in shares)	(20,000)
Total Granted and Outstanding (in shares)	1,989,000
Approved for grant (in shares)	636,000
Total Awarded and Unvested, end of period (in shares)	2,625,000	1,295,000
Weighted Average Grant Date Fair Value
Total Granted and Outstanding, beginning of period, Grant Date Fair Value (in dollars per share)	$ 9.94
Granted, Grant Date Fair Value (in dollars per share)	$ 17.69	$ 7.90	$ 5.65
Exercised, Grant Date Fair Value (in dollars per share)	$ 7.25
Total Granted and Outstanding, end of period, Grant Date Fair Value (in dollars per share)	$ 12.75	$ 9.94
Weighted Average Exercise Price
Total Granted and Outstanding, beginning of period, Weighted Average Exercise Price (in dollars per share)	$ 20.20
Granted, Weighted Average Exercise Price (in dollars per share)	$ 18.40
Exercised, Weighted Average Exercise Price (in dollars per share)	$ 12.54
Total Granted and Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 19.63
Approved for grant, Weighted Average Exercise Price (in dollars per share)	$ 17.62
Total Awarded and Outstanding, end of period, Weighted Average Exercise Price (in dollars per share)	$ 19.14	$ 20.20