Charges Related To Restructuring Activities (Details) - USD ($)	3 Months Ended			6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Restructuring Reserve [Roll Forward]
Beginning Balance	$ 6,549,000	$ 7,027,000		$ 7,027,000
Charges	1,685,000	1,392,000	$ 1,321,000	3,077,000	$ 2,013,000
Payments	(2,216,000)	(1,870,000)		(4,086,000)	(2,113,000)
Ending Balance	6,018,000	6,549,000		6,018,000
Severance
Restructuring Reserve [Roll Forward]
Beginning Balance	6,545,000	7,023,000		7,023,000
Charges	1,412,000	1,319,000
Payments	(1,943,000)	(1,797,000)
Ending Balance	6,014,000	6,545,000		6,014,000
Contract Termination
Restructuring Reserve [Roll Forward]
Beginning Balance	4,000	4,000		4,000
Charges	273,000	73,000
Payments	(273,000)	(73,000)
Ending Balance	4,000	4,000		4,000
All Other
Restructuring Reserve [Roll Forward]
Beginning Balance	166,000	406,000		406,000
Charges	82,000	36,000	346,000	118,000	165,000
Payments	(82,000)	(276,000)
Ending Balance	166,000	166,000		166,000
All Other | Severance
Restructuring Reserve [Roll Forward]
Beginning Balance	166,000	406,000		406,000
Charges	82,000	36,000			165,000
Payments	(82,000)	(276,000)
Ending Balance	166,000	166,000		166,000
All Other | Contract Termination
Restructuring Reserve [Roll Forward]
Beginning Balance	0	0		0
Charges	0	0
Payments	0	0
Ending Balance	0	0		0
Europe
Restructuring Reserve [Roll Forward]
Beginning Balance	6,043,000	6,410,000		6,410,000
Charges	1,575,000	665,000	320,000	2,240,000	640,000
Payments	(1,869,000)	(1,032,000)
Ending Balance	5,749,000	6,043,000		5,749,000
Europe | Severance
Restructuring Reserve [Roll Forward]
Beginning Balance	6,039,000	6,406,000		6,406,000
Charges	1,302,000	592,000			640,000
Payments	(1,596,000)	(959,000)
Ending Balance	5,745,000	6,039,000		5,745,000
Europe | Contract Termination
Restructuring Reserve [Roll Forward]
Beginning Balance	4,000	4,000		4,000
Charges	273,000	73,000
Payments	(273,000)	(73,000)
Ending Balance	4,000	4,000		4,000
North America
Restructuring Reserve [Roll Forward]
Beginning Balance	340,000	211,000		211,000
Charges	28,000	691,000	$ 655,000	719,000	1,208,000
Restructuring Reserve, Accrual Adjustment	28,000			719,000
Payments	(265,000)	(562,000)
Ending Balance	103,000	340,000		103,000
North America | Severance
Restructuring Reserve [Roll Forward]
Beginning Balance	340,000	211,000		211,000
Charges	28,000	691,000			1,164,000
Payments	(265,000)	(562,000)
Ending Balance	103,000	340,000		103,000
North America | Contract Termination
Restructuring Reserve [Roll Forward]
Beginning Balance	0	0		0
Charges					$ 44,000
Restructuring Reserve, Accrual Adjustment	0	0
Payments	0	0
Ending Balance	$ 0	$ 0		$ 0