Summary of Significant Accounting Policies (Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss	$ (15,723)	$ (21,074)	$ (21,808)
Accumulated Net Unrealized Investment Gain (Loss)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss	46	422	530
Accumulated other comprehensive loss, tax effect	21	160	200
Accumulated Defined Benefit Plans Adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss	(15,769)	(21,496)	(22,338)
Accumulated other comprehensive loss, tax effect	$ (5,692)	$ (7,809)	$ (8,120)