Stock-Based Compensation (Summary of Restricted Stock Unit and Stock Option Activity) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Restricted Stock Units [Member]
RSUs Number of Shares
Outstanding, beginning of period (in shares)	725,597	1,056,597	361,668
Granted (in shares)	483,387	321,500	996,597
Expired or canceled (in shares)		(281,560)	(20,000)
Vested/exercised (in shares)	(52,500)	(370,940)	(281,668)
Outstanding, end of period (in shares)	1,156,484	725,597	1,056,597
Weighted Average Grant Date Fair Value
Outstanding, beginning of period, Weighted Average Grant Date Fair Value (in dollars per share)	$ 25.28	$ 26.54	$ 17.30
Granted, Weighted Average Grant Date Fair Value (in dollars per share)	19.14	23.07	27.10
Expired or canceled, Weighted Average Grant Date Fair Value (in dollars per share)		23.89	24.77
Vested/exercised, Weighted Average Grant Date Fair Value (in dollars per share)	18.74	27.07	16.76
Outstanding, end of period, Weighted Average Grant Date Fair Value (in dollars per share)	$ 22.64	$ 25.28	$ 26.54
Stock Options [Member]
Stock Options Number of Shares
Outstanding, beginning of period (in shares)	1,998,000	1,989,000	1,295,000
Granted (in shares)	274,000	259,000	714,000
Expired or canceled (in shares)		(250,000)
Vested/exercised (in shares)	(97,500)		(20,000)
Outstanding, end of period (in shares)	2,174,500	1,998,000	1,989,000
Weighted-Average Grant Date Fair Value
Outstanding, beginning of period, Grant Date Fair Value (in dollars per share)	$ 19.62	$ 19.63	$ 20.20
Granted, Grant Date Fair Value (in dollars per share)	16.20	16.07	18.40
Expired or canceled, Grant Date Fair Value (in dollars per share)		15.97
Vested/exercised, Grant Date Fair Value (in dollars per share)	12.72		12.54
Outstanding, end of period, Grant Date Fair Value (in dollars per share)	$ 19.50	$ 19.62	$ 19.63