Stock-Based Compensation And Stock Repurchases (Schedule Of Restricted Stock Units Issued And Vested) (Details) - Restricted Stock Units (RSUs) [Member]	Sep. 30, 2018 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options, Grants	213,281
Number of options, Vested	97,155
Number of options, Unvested	116,126
March 10, 2016 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options, Grants	62,528
Number of options, Vested	48,837
Number of options, Unvested	13,691
April 11, 2016 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options, Grants	5,625
Number of options, Vested	1,406
Number of options, Unvested	4,219
March 23, 2017 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options, Grants	63,144
Number of options, Vested	46,912
Number of options, Unvested	16,232
August 29, 2017 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options, Grants	7,394
Number of options, Unvested	7,394
January 2, 2018 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options, Grants	29,393
Number of options, Unvested	29,393
April 12, 2018 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options, Grants	29,596
Number of options, Unvested	29,596
April 13, 2018 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options, Grants	14,669
Number of options, Unvested	14,669
July 6, 2018 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options, Grants	932
Number of options, Unvested	932
Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options, Grants	95,221
Directors [Member] | March 10, 2016 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options, Grants	35,147
Directors [Member] | March 23, 2017 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options, Grants	30,681
Directors [Member] | January 2, 2018 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options, Grants	29,393
Management [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options, Grants	118,060
Management [Member] | March 10, 2016 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options, Grants	27,381
Management [Member] | April 11, 2016 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options, Grants	5,625
Management [Member] | March 23, 2017 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options, Grants	32,463
Management [Member] | August 29, 2017 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options, Grants	7,394
Management [Member] | April 12, 2018 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options, Grants	29,596
Management [Member] | April 13, 2018 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options, Grants	14,669
Management [Member] | July 6, 2018 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options, Grants	932