Commitments and Contingencies (Details Textual) $ in Millions	3 Months Ended
	Sep. 30, 2018 USD ($) plaintiff	Mar. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2014 USD ($)
Ecoserv | Environmental services
Loss Contingencies [Line Items]
Escrow deposit				$ 8.0
Settled litigation | Ecoserv | Environmental services
Loss Contingencies [Line Items]
Litigation settlement, awarded from other party			$ 22.0
Litigation settlement, awarded from other party, net of tax			$ 17.4
Litigation settlement, awarded to other party		$ 14.0
Damage from fire | Casualty event
Loss Contingencies [Line Items]
Loss contingency, number of plaintiffs | plaintiff	23
Loss contingency, damages sought, value	$ 1.5
Loss contingency, costs incurred	4.6
Insurance receivable	3.8
Fire-related costs, net of insurance proceeds	0.8
Damage from fire | Inventory and property, plant and equipment
Loss Contingencies [Line Items]
Loss contingency, costs incurred	1.9
Damage from fire | Property-related cleanup and other costs
Loss Contingencies [Line Items]
Loss contingency, costs incurred	1.9
Damage from fire | Self-insured retention for third-party claims
Loss Contingencies [Line Items]
Loss contingency, costs incurred	$ 0.8