Stock-Based Compensation (Schedule of Qualified Stock Option Activity) (Details) (Qualified Stock Options, USD $)	3 Months Ended
	Mar. 31, 2013
Qualified Stock Options
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding at beginning of year	330,730
Granted	0
Exercised	(32,900)
Canceled	(4,300)
Outstanding at March 31, 2013	293,530
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Granted, Exercise Price, in dollars per share	$ 0.00	[1]
Exercised, Exercise Price, in dollars per share	$ 17.17	[1]
Cancelled, Exercise Price, in dollars per share	$ 23.84	[1]
Outstanding at March 31, 2013, Exercise Price, in dollars per share	$ 22.31	[1]
Exercisable at March 31, 2013	159,930
Excercisable at March 31, 2013, Exercise Price, in dollars per share	$ 19.96	[1]
Available for grant at March 31, 2013	113,900

[1] Weighted Averages