Stock-Based Compensation Plan (Summary Of Stock Option Activities) (Details) - Stock Options [Member] - USD ($) $ / shares in Units, $ in Millions	6 Months Ended
	Jun. 30, 2018	Jun. 30, 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		230,500
Options exercised, Number of Shares	(9,393)	(205,100)
Options outstanding at end of period, Number of Shares	850,167	1,453,655
Options exercisable, Number of Shares	593,043	982,531
Options outstanding at beginning of period, Weighted Average Exercise Price	$ 16.44	$ 16.31
Options granted, Weighted Average Exercise Price		16.80
Options exercised, Weighted Average Exercise Price	14.76	10.30
Options outstanding at end of period, Weighted Average Exercise Price	16.46	17.24
Options exercisable, Weighted Average Exercise Price	$ 17.71	$ 18.30
Weighted average remaining term	6 years 1 month 6 days	4 years 9 months 18 days
Options outstanding at end of period, Aggregate Intrinsic Value (in thousands)	$ 5.9