Quarterly Results of Operations - Textual (Details) - USD ($)	3 Months Ended			12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Business Acquisition, Contingent Consideration [Line Items]
Foreign exchange gain (loss)	$ 13,324,000	$ 660,000		$ 23,258,000	$ (18,137,000)	$ 213,000
Cost of services sold	1,534,000	7,480,000		18,416,000	24,350,000	21,003,000
Income attributable to fair value adjustments				(374,000)	(4,819,000)	8,227,000
Asset Impairment Charges	56,732,000			80,057,000	4,415,000	$ 48,524,000
Goodwill, Impairment Loss				74,560,000	3,238,000
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount	49,447,000	226,466,000
Contingent Payment [Member]
Business Acquisition, Contingent Consideration [Line Items]
Income attributable to fair value adjustments	$ 8,979,000	18,173,000		(3,679,000)	(6,021,000)
All Other [Domain]
Business Acquisition, Contingent Consideration [Line Items]
Goodwill, Impairment Loss				$ 4,691,000	$ 0
Experiential and Non-material [Member]
Business Acquisition, Contingent Consideration [Line Items]
Goodwill, Impairment Loss		$ 18,893,000	$ 29,631,000