Other - Other General Expense - Net (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Other Income and Expenses [Abstract]
Provisions for environmental matters - net	$ 765	$ 519
Loss (gain) on sale or disposition of assets	2,225	(243)
Total	$ 2,990	$ 276