Impairment, Restructuring and Other Exit Costs - Restructuring Liability (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Restructuring Reserve [Roll Forward]
Restructuring charges accrued during the period	$ 333,988	$ 0	$ 388,027	$ 0
Severance
Restructuring Reserve [Roll Forward]
Balance as of January 1, 2019			0
Restructuring charges accrued during the period			34,617
Cash payments / settlements during the period			13,987
Currency translation			(568)
Balance as of September 30, 2019	20,062		20,062
Lease Exit Costs
Restructuring Reserve [Roll Forward]
Balance as of January 1, 2019			0
Restructuring charges accrued during the period			5,289
Cash payments / settlements during the period			93
Currency translation			0
Balance as of September 30, 2019	5,196		5,196
Other
Restructuring Reserve [Roll Forward]
Balance as of January 1, 2019			0
Restructuring charges accrued during the period			327
Cash payments / settlements during the period			568
Currency translation			0
Balance as of September 30, 2019	(241)		(241)
Total
Restructuring Reserve [Roll Forward]
Balance as of January 1, 2019			0
Restructuring charges accrued during the period			40,233
Cash payments / settlements during the period			14,648
Currency translation			(568)
Balance as of September 30, 2019	$ 25,017		$ 25,017