Leases - Summary of Leases Table (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2019 USD ($)
Leases [Abstract]
Operating leases - Other assets	$ 6,923
Finance leases - Net property, plant and equipment	8,374
Operating leases - Accrued liabilities	4,515
Finance leases - Short-term debt	8,381
Operating leases - Other liabilities	3,302
Total lease liabilities - operating leases	$ 7,817
Weighted-average remaining lease term (years) - operating leases	4 years
Weighted-average remaining lease term (years) - finance leases	1 year
Weighted-average discount rate - operating leases	4.60%
Weighted-average discount rate - finance leases	2.90%
Additions to ROU assets and lease liabilities - finance leases	$ 8,500