Pensions and Other Postretirement Benefit Plans (Schedule of Pension Plans with Projected Benefit Obligation and Accumulated Benefit Obligation in Excess of Plan Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Plans with projected benefit obligation in excess of plan assets:
Projected benefit obligation	$ 123,261	$ 131,717
Fair value of plan assets	86,547	90,149
Plans with accumulated benefit obligation in excess of plan assets:
Accumulated benefit obligation	120,869	129,698
Fair value of plan assets	$ 86,062	$ 90,149