Summary of Significant Accounting Policies (Summary Of Gross Carrying Value And Accumulated Amortization Related To The Company's Intangible Items) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 17,228	$ 17,228
Accumulated Amortization	14,913	13,382
Customer List Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	15,411	15,411
Accumulated Amortization	13,255	11,914
Software Intangible [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	1,817	1,817
Accumulated Amortization	$ 1,658	$ 1,468