Stock-Based Compensation Plan (Summary Of Stock Option Activities) (Details) - Stock Options [Member] - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options outstanding at beginning of period, Number of Shares	859,560	1,428,255
Options granted, Number of Shares		190,500
Options exercised, Number of Shares	(1,893)	(60,875)
Options outstanding at end of period, Number of Shares	857,667	1,557,880
Options exercisable, Number of Shares	521,021	1,009,555
Options outstanding at beginning of period, Weighted Average Exercise Price	$ 16.44	$ 16.31
Options granted, Weighted Average Exercise Price		15.89
Options exercised, Weighted Average Exercise Price	12.64	8.44
Options outstanding at end of period, Weighted Average Exercise Price	16.45	16.57
Options exercisable, Weighted Average Exercise Price	$ 17.56	$ 18.21
Weighted average remaining term	6 years 1 month 6 days	4 years 6 months
Options outstanding at end of period, Aggregate Intrinsic Value (in thousands)	$ 4.6