Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jan. 01, 2018
Allowance for doubtful accounts receivable
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	$ 33,181	$ 33,133	$ 35,087
Charged to Expenses	11,914	8,022	9,192
Deductions	(8,690)	(8,751)	(9,907)
Translation Adjustments	772	777	(1,239)
Balance at End of Period	27,678	33,181	33,133
Liability recognized in accordance with ASC 606	(33,181)	(33,133)	(35,087)	$ (23,682)
Allowance for doubtful accounts receivable | Accounting Standards Update 2014-09
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Liability recognized in accordance with ASC 606				$ 9,500
Deferred tax valuation allowance
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	20,178	18,907	26,329
Charged to Expenses	5,683	1,411	2,160
Deductions	(2,599)	(1,275)	(9,517)
Translation Adjustments	(190)	1,135	(65)
Balance at End of Period	23,072	20,178	18,907
Liability recognized in accordance with ASC 606	$ (20,178)	$ (18,907)	$ (26,329)