Stock Options and Incentive Plans (Schedules of Stock Option Activity) (Details) - Employee Stock Option [Member] - $ / shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Shares
Shares under option	187,233	228,533	507,313
Options canceled
Options exercised	98,460	41,300	278,780
Shares under option at December 31	88,773	187,233	228,533
Options exercisable at December 31	88,773	187,233	228,533
Weighted Average Exercise Price
Shares under option January 1	$ 18.99	$ 18.94	$ 19.45
Options canceled
Options exercised	$ 19.27	$ 18.71	$ 19.87
Shares under option December 31	18.67	18.99	18.94
Options exercisable December 31	$ 18.67	$ 18.99	$ 18.94