Stock Options (Schedule of Qualified Stock Option Activity) (Details) (Qualified Stock Options, USD $)	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Qualified Stock Options
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options outstanding at beginning of year	330,730		377,480		360,130
Granted	49,000		61,000		35,000
Exercised	(81,880)		(99,650)		(15,650)
Canceled	(5,500)		(8,100)		(2,000)
Options outstanding at end of year	292,350		330,730		377,480
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Outstanding at beginning of year, Exercise Price, in dollars per share	$ 21.82	[1]	$ 19.27	[1]	$ 18.29	[1]
Granted, Exercise Price, in dollars per share	$ 42.70	[1]	$ 32.76	[1]	$ 26.45	[1]
Exercised, Exercise Price, in dollars per share	$ 16.77	[1]	$ 19.26	[1]	$ 12.03	[1]
Cancelled, Exercise Price, in dollars per share	$ 24.24	[1]	$ 17.20	[1]	$ 24.69	[1]
Outstanding at end of year, Exercise Price, in dollars per share	$ 26.68	[1]	$ 21.82	[1]	$ 19.27	[1]
Options exercisable at end of year	154,950		192,830		243,180
Exercisable at end of year, Exercise Price, in dollars per share	$ 21.57	[1]	$ 19.48	[1]	$ 19.32	[1]
Options available for grant at end of year	66,100		109,600		162,500

[1] Weighted Averages