Severance and Restructuring (Components of and Changes in Severance and Restructuring Accruals) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Restructuring Cost and Reserve [Line Items]
Provision		$ 383	$ 2,550
Employee Termination Costs [Member]
Restructuring Cost and Reserve [Line Items]
Balance	$ 562	1,326
Provision	647	1,038
Utilization	(1,129)	(1,802)
Balance	80	562	1,326
Restructuring and Other [Member]
Restructuring Cost and Reserve [Line Items]
Balance	1,077	1,786
Provision	564	627
Utilization	(1,056)	(1,336)
Balance	$ 585	$ 1,077	$ 1,786