Restructuring Activities - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Restructuring And Related Activities [Abstract]
Restructuring and related activities	$ 0	$ 0	$ (439)
Restructuring And Related Cost Description	The 2015 Program included provisions for the reduction of total headcount by approximately 65 employees globally. The Company substantially completed all of the initiatives under the 2015 Program in 2016 and settlement of these charges occurred primarily in 2016 as well. During the fourth quarter of 2016, the Company recognized a restructuring credit of $0.4 million in connection with the 2015 Program, due to customary and routine adjustments to initial estimates for employee separation costs.