Accumulated Other Comprehensive Income (Loss) (Components of Accumulated Other Comprehensive Income (Loss)) (Details) - Accumulated Defined Benefit Plans Adjustment Including Portion Attributable to Noncontrolling Interest [Member] - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss, net of tax	$ (8,188)	$ (7,567)
Pension Benefits [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss, net of tax	(10,304)	(9,707)
Accumulated other comprehensive loss, tax	6,282	6,120
Postretirement Benefit Plan [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss, net of tax	2,116	2,140
Accumulated other comprehensive loss, tax	$ 527	$ 533