Property, Plant and Equipment - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Depreciation		$ 2,579	$ 1,711	$ 946
Interest costs capitalized		4,400	3,600
Construction in progress
Property, Plant and Equipment [Line Items]
Payroll		$ 1,800	$ 800
Building and improvements
Property, Plant and Equipment [Line Items]
Amount reclassified from Construction in process to Building and improvements	$ 37,000