Charges Related To Restructuring Activities - (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Restructuring Reserve [Roll Forward]
Beginning Balance				$ 1,682,000				$ 4,005,000	$ 1,682,000	$ 4,005,000	$ 2,169,000
Charges	$ (8,188,000)	$ (1,628,000)	$ (1,321,000)	(692,000)	$ (1,816,000)	$ (920,000)	$ (344,000)	(401,000)	(11,829,000)	(3,481,000)	(12,274,000)
Payments									(6,484,000)	(5,804,000)	(10,438,000)
Ending Balance	7,027,000				1,682,000				7,027,000	1,682,000	4,005,000
Severance
Restructuring Reserve [Roll Forward]
Beginning Balance				1,657,000				3,704,000	1,657,000	3,704,000	2,049,000
Charges									(11,562,000)	(3,593,000)	(11,325,000)
Payments									(6,196,000)	(5,640,000)	(9,670,000)
Ending Balance	7,023,000				1,657,000				7,023,000	1,657,000	3,704,000
Contract Terminations
Restructuring Reserve [Roll Forward]
Beginning Balance				25,000				301,000	25,000	301,000	120,000
Charges									(267,000)	112,000	(949,000)
Payments									(288,000)	(164,000)	(768,000)
Ending Balance	4,000				25,000				4,000	25,000	301,000
Europe
Restructuring Reserve [Roll Forward]
Beginning Balance				181,000				383,000	181,000	383,000
Charges									(9,579,000)	(1,773,000)	(1,975,000)
Payments									(3,350,000)	(1,975,000)	(1,592,000)
Ending Balance	6,410,000				181,000				6,410,000	181,000	383,000
Europe | Severance
Restructuring Reserve [Roll Forward]
Beginning Balance				181,000				249,000	181,000	249,000
Charges									(9,356,000)	(1,773,000)	(1,753,000)
Payments									(3,131,000)	(1,841,000)	(1,504,000)
Ending Balance	6,406,000				181,000				6,406,000	181,000	249,000
Europe | Contract Terminations
Restructuring Reserve [Roll Forward]
Beginning Balance				0				134,000	0	134,000
Charges									(223,000)	0	(222,000)
Payments									(219,000)	(134,000)	(88,000)
Ending Balance	4,000				0				4,000	0	134,000
Other Segments
Restructuring Reserve [Roll Forward]
Beginning Balance				820,000				1,016,000	820,000	1,016,000	1,266,000
Charges									(633,000)	(349,000)	(1,410,000)
Payments									(1,047,000)	(545,000)	(1,660,000)
Ending Balance	406,000				820,000				406,000	820,000	1,016,000
Other Segments | Severance
Restructuring Reserve [Roll Forward]
Beginning Balance				820,000				1,016,000	820,000	1,016,000	1,266,000
Charges									(633,000)	(349,000)	(1,410,000)
Payments									(1,047,000)	(545,000)	(1,660,000)
Ending Balance	406,000				820,000				406,000	820,000	1,016,000
Other Segments | Contract Terminations
Restructuring Reserve [Roll Forward]
Beginning Balance				0				0	0	0	0
Charges									0	0	0
Payments									0	0	0
Ending Balance	0				0				0	0	0
North America
Restructuring Reserve [Roll Forward]
Beginning Balance				681,000				2,606,000	681,000	2,606,000	903,000
Charges									(1,617,000)	(1,359,000)	(8,889,000)
Payments									(2,087,000)	(3,284,000)	(7,186,000)
Ending Balance	211,000				681,000				211,000	681,000	2,606,000
North America | Severance
Restructuring Reserve [Roll Forward]
Beginning Balance				656,000				2,439,000	656,000	2,439,000	783,000
Charges									(1,573,000)	(1,471,000)	(8,162,000)
Payments									(2,018,000)	(3,254,000)	(6,506,000)
Ending Balance	211,000				656,000				211,000	656,000	2,439,000
North America | Contract Terminations
Restructuring Reserve [Roll Forward]
Beginning Balance				$ 25,000				$ 167,000	25,000	167,000	120,000
Charges									(44,000)	112,000	(727,000)
Payments									(69,000)	(30,000)	(680,000)
Ending Balance	$ 0				$ 25,000				$ 0	$ 25,000	$ 167,000