Summary Of Significant Accounting Policies (Components Of Accumulated Other Comprehensive Income (Loss), Net Of Tax) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance		$ 354,450	$ 305,830	$ 250,936
Current Period Change		(9,709)	2,150	(9,128)
Balance		388,187	354,450	305,830
Unrealized Holding Gains (Losses) On Available-For-Sale Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance		2,600
Current Period Change		(5,916)
Adoption of ASU 2018-02	[1]	361
Balance		(2,955)	2,600
Unrealized Actuarial Losses On Pension Plan [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance		(2,054)
Current Period Change		(3,004)
Adoption of ASU 2018-02	[1]	(638)
Balance		(5,696)	(2,054)
Unrealized Loss On Derivative Instrument [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance
Current Period Change		(789)
Adoption of ASU 2018-02	[1]
Balance		(789)
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance		546	(1,604)	7,524
Current Period Change		(9,709)	2,150	(9,128)
Adoption of ASU 2018-02	[1]	(277)
Balance		$ (9,440)	$ 546	$ (1,604)

[1] The adoption of Accounting Standards Update ("ASU") 2018-02 "Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income" in the first quarter of 2018 allowed the Corporation to reclassify certain stranded tax effects arising from the enactment of the Tax Cuts and Jobs Act ("Tax Act") in December 2017 from accumulated other comprehensive income to retained earnings. See "Adoption of New Accounting Standards" for more information regarding the effects of adopting ASU 2018-02.