SCHEDULE II. VALUATION AND QUALIFYING ACCOUNTS (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Allowance for Doubtful Accounts
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	$ 4,731	$ 11,800	$ 25,649
Charged to Cost and Expenses	372	5,346	(38)
Due to Currency Translation Adjustments	(154)	533	(320)
Other	(315)	(12,948)	(13,491)
Balance at End of Period	4,634	4,731	11,800
Deferred Tax Assets - Valuation Allowance
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	174,227	146,097	110,680
Charged to Cost and Expenses	(19,990)	33,041	38,490
Due to Currency Translation Adjustments	(8,693)	10,097	(6,323)
Other	(6,682)	(15,008)	3,250
Balance at End of Period	138,862	174,227	$ 146,097
Change in Estimate of Interest Deductions
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Decrease in valuation allowance		5,400
Capital Loss Carryforward
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Decrease in valuation allowance		1,100
Pension Adjustments
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Decrease in valuation allowance	$ 11,600
US tax rate change
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Decrease in valuation allowance		$ 4,600