Stock and Other Incentive Plans (Details 1) - Employee Stock Purchase Plan [Member] - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Stock Options Outstanding:
Options outstanding, beginning of year (shares)	318,100	316,321	340,958
Granted (shares)	203,836	206,824	198,450
Exercised (shares)	(16,716)	(32,076)	(57,924)
Forfeited (shares)	(40,897)	(40,659)	(22,081)
Expired (shares)	(135,790)	(132,310)	(143,082)
Outstanding, end of period (shares)	328,533	318,100	316,321
Exercisable, end of period (shares)	328,533	318,100	316,321
Weighted-average exercise price:
Options outstanding, beginning of year (in USD per share)	$ 25.00	$ 23.69	$ 20.70
Options granted during the year (in USD per share)	27.30	25.77	24.07
Options exercised during the year (in USD per share)	24.01	24.31	21.40
Options forfeited during the year (in USD per share)	24.06	25.01	23.16
Options expired during the year (in USD per share)	23.55	23.22	18.11
Options outstanding, end of year (in USD per share)	24.17	25.00	23.69
Weighted-average fair value of options granted during the year (calculated as of the grant date) (in USD per share)	$ 7.81	$ 6.31	$ 5.37
Intrinsic value of options exercised during the year	$ 71	$ 271	$ 634
Intrinsic value of options outstanding (calculated as of December 31)	1,402	2,683	2,098
Intrinsic value of options exercisable (calculated as of December 31)	$ 1,402	$ 2,683	$ 2,098
Exercise prices of options outstanding (calculated as of December 31) (in USD per share)	$ 24.17	$ 25.00	$ 23.69
Weighted-average contractual life of outstanding options (calculated as of December 31, in years)	24 days	24 days	24 days