Stock-Based Compensation (Summary of Stock Option Activity) (Details) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Number of Shares
Outstanding - beginning of year, number of shares	146,000
Granted, number of shares	0	0	0
Exercised, number of shares	(2,500)
Canceled or expired, number of shares	0
Outstanding - end of year, number of shares	143,500	146,000
Options exercisable, number of shares	143,500
Weighted Average Exercise Price
Outstanding - beginning of year, Weighted Average Exercise Price (in dollars per share)	$ 16.71
Granted, Weighted Average Exercise Price (in dollars per share)	$ 0.00
Exercised, Weighted Average Exercise Price (in dollars per share)	$ 14.12
Canceled or Expired, Weighted Average Exercise Price (in dollars per share)	$ 0.00
Outstanding - end of year, Weighted Average Exercise Price (in dollars per share)	$ 16.76	$ 16.71
Options Exercisable - end of year, Weighted Average Exercise Price	$ 16.76
Outstanding - end of year, weighted average remaining contractual term	1 year 8 months 12 days
Options Exercisable, Weighted Average remaining contractual term	1 year 8 months 12 days
Outstanding - end of year, Aggregate intrinsic value	$ 6.6
Options Exercisable, Aggregate intrinsic value	$ 6.6