Stock-Based Compensation (Summary of Restricted Stock Unit Awards Activity) (Details) (Restricted Stock Units [Member], USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Restricted Stock Units [Member]
Number of Shares
Granted and Unvested, beginning of period (in shares)	361,668
Vested (in shares)	(281,668)
Granted (in shares)	996,597
Forfeited (in shares)	(20,000)
Total Granted and Unvested (in shares)	1,056,597	361,668
Approved for grant (in shares)	749,000
Total Awarded and Unvested, end of period (in shares)	1,805,597
Weighted Average Grant Date Fair Value
Total Granted and Unvested, beginning of period, Weighted Average Grant Date Fair Value (in dollars per share)	$ 17.30
Vested, Weighted Average Grant Date Fair Value (in dollars per share)	$ 16.76
Granted, Weighted Average Grant Date Fair Value (in dollars per share)	$ 27.10	$ 19.87	$ 14.39
Forfeited, Weighted Average Grant Date Fair Value (in dollars per share)	$ 24.77
Total Granted and Unvested, end of period, Weighted Average Grant Date Fair Value (in dollars per share)	$ 26.54	$ 17.30
Aggregate Intrinsic Value
Total Granted and Unvested, beginning of period, Aggregate Intrinsic Value	$ 9,512
Vested, Aggregate Intrinsic Value	8,049
Granted, Aggregate Intrinsic Value	23,988
Total Granted and Unvested, Aggregate Intrinsic Value	25,432	9,512
Approved for grant, Aggregate Intrinsic Value	18,028
Total Awarded and Unvested, end of period, Aggregate Intrinsic Value	$ 43,461