Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019
Components of property, plant and equipment
Land	$ 40,336	$ 40,442	$ 39,552
Land improvements and leasehold improvements	95,327	103,148	82,681
Buildings and storage facilities	381,258	373,961	337,631
Machinery and equipment	861,812	835,156	481,454
Construction in progress	41,824	59,993	151,895
Property, plant and equipment, gross	1,420,557	1,412,700	1,093,213
Less: accumulated depreciation	498,972	474,282	421,408
Property, plant and equipment, net	$ 921,585	$ 938,418	$ 671,805