Goodwill and Intangible Assets - Goodwill activity (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Goodwill, Roll forward
Goodwill, gross, at the beginning of the year		$ 403,129
Accumulated impairment losses		(24,291)
Goodwill, net, at the beginning of the year	$ 378,838
Foreign currency translation adjustment	(17,736)
Goodwill, net, at the end of the year	361,102
Americas
Goodwill, Roll forward
Goodwill, gross, at the beginning of the year		268,049
Goodwill, net, at the beginning of the year	268,049
Foreign currency translation adjustment	(10,810)
Goodwill, net, at the end of the year	257,239
Europe
Goodwill, Roll forward
Goodwill, gross, at the beginning of the year		135,080
Accumulated impairment losses		$ (24,291)
Goodwill, net, at the beginning of the year	110,789
Foreign currency translation adjustment	(6,926)
Goodwill, net, at the end of the year	$ 103,863