Stock Options and Incentive Plans (Schedules of Stock Option Activity) (Details) (Employee Stock Option [Member], USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Employee Stock Option [Member]
Shares
Shares under option	228,533	507,313	597,313
Options canceled			23,300
Options exercised	41,300	278,780	66,700
Shares under option at December 31	187,233	228,533	507,313
Options exercisable at December 31	187,233	228,533	507,313
Weighted Average Exercise Price
Shares under option January 1	$ 18.94	$ 19.45	$ 19.54
Options canceled			$ 21.23
Options exercised	$ 18.71	$ 19.87	$ 19.65
Shares under option December 31	$ 18.99	$ 18.94	$ 19.45
Options exercisable December 31	$ 18.99	$ 18.94	$ 19.45