Stock-Based Compensation Plan (Summary Of Stock Option Activities) (Details) - Stock Options [Member] - $ / shares	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options outstanding at beginning of period, Number of Shares	1,428,255	1,189,255
Options granted, Number of Shares	230,500	245,000
Options exercised, Number of Shares	(205,100)
Options forfeited/cancelled, Number of Shares		(6,000)
Options outstanding at end of period, Number of Shares	1,453,655	1,428,255
Options exercisable, Number of Shares	982,531	1,013,680
Options outstanding at beginning of period, Weighted Average Exercise Price	$ 16.31	$ 18.08
Options granted, Weighted Average Exercise Price	16.80	7.87
Options exercised, Weighted Average Exercise Price	10.30
Options forfeited/cancelled, Weighted Average Exercise Price		21.99
Options outstanding at end of period, Weighted Average Exercise Price	17.24	16.31
Options exercisable, Weighted Average Exercise Price	$ 18.30	$ 17.38
Weighted average remaining term	4 years 9 months 18 days	4 years 10 months 24 days