Charges Related To Restructuring Activities - Narrative (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 Cost and Reserve [Line Items]
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)
Expected payout period									12 months
Severance
Restructuring Cost and Reserve [Line Items]
Charges									$ (11,562,000)	(3,593,000)	(11,325,000)
Payments									(6,196,000)	(5,640,000)	(9,670,000)
Contract Terminations
Restructuring Cost and Reserve [Line Items]
Charges									(267,000)	112,000	(949,000)
Payments									(288,000)	(164,000)	(768,000)
North America
Restructuring Cost and Reserve [Line Items]
Charges									(1,617,000)	(1,359,000)	(8,889,000)
Payments									(2,087,000)	(3,284,000)	(7,186,000)
North America | Severance
Restructuring Cost and Reserve [Line Items]
Charges									(1,573,000)	(1,471,000)	(8,162,000)
Payments									(2,018,000)	(3,254,000)	(6,506,000)
North America | Contract Terminations
Restructuring Cost and Reserve [Line Items]
Charges									(44,000)	112,000	(727,000)
Payments									(69,000)	(30,000)	(680,000)
Europe
Restructuring Cost and Reserve [Line Items]
Charges									(9,579,000)	(1,773,000)	(1,975,000)
Payments									(3,350,000)	(1,975,000)	(1,592,000)
Europe | Severance
Restructuring Cost and Reserve [Line Items]
Charges									(9,356,000)	(1,773,000)	(1,753,000)
Payments									(3,131,000)	(1,841,000)	(1,504,000)
Europe | Contract Terminations
Restructuring Cost and Reserve [Line Items]
Charges									(223,000)	0	(222,000)
Payments									(219,000)	(134,000)	(88,000)
Other Segments
Restructuring Cost and Reserve [Line Items]
Charges									(633,000)	(349,000)	(1,410,000)
Payments									(1,047,000)	(545,000)	(1,660,000)
Other Segments | Severance
Restructuring Cost and Reserve [Line Items]
Charges									(633,000)	(349,000)	(1,410,000)
Payments									(1,047,000)	(545,000)	(1,660,000)
Other Segments | Contract Terminations
Restructuring Cost and Reserve [Line Items]
Charges									0	0	0
Payments									$ 0	$ 0	$ 0