Commitments and Contingencies (Details Textual) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Mar. 31, 2014
Loss Contingencies [Line Items]
Guarantee obligations due to closure of bonds		$ 400,000	$ 4,000,000.0
Asset retirement obligation		$ 1,100,000	1,000,000.0
Minimum [Member]
Loss Contingencies [Line Items]
Operating lease term		1 year
Maximum [Member]
Loss Contingencies [Line Items]
Operating lease term		9 years
Ecoserv [Member] | Environmental services [Member]
Loss Contingencies [Line Items]
Escrow deposit		$ 8,000,000			$ 8,000,000	$ 8,000,000
Ecoserv [Member] | Environmental services [Member] | Pending Litigation [Member]
Loss Contingencies [Line Items]
Sales price, damage model		100,000,000
Loss contingency, damages sought, value		20,000,000
Ecoserv [Member] | Environmental services [Member] | Settled litigation [Member]
Loss Contingencies [Line Items]
Litigation settlement, amount from other party		22,000,000
Released 9 months from closing date | Ecoserv [Member] | Environmental services [Member]
Loss Contingencies [Line Items]
Escrow deposit					4,000,000
Released 9 months from closing date | Ecoserv [Member] | Environmental services [Member] | Pending Litigation [Member]
Loss Contingencies [Line Items]
Escrow deposit						$ 4,000,000
Released 18 months from closing date | Ecoserv [Member] | Environmental services [Member]
Loss Contingencies [Line Items]
Escrow deposit					$ 4,000,000
Scenario, forecast [Member] | Ecoserv [Member] | Environmental services [Member] | Settled litigation [Member]
Loss Contingencies [Line Items]
Litigation settlement, awarded to other party	$ 14,000,000
Letters of credit in favor of insurance company [Member]
Loss Contingencies [Line Items]
Operating leases, rent expense		23,900,000	21,000,000	$ 22,600,000
Other commitment		2,200,000	3,000,000
Health claims [Member]
Loss Contingencies [Line Items]
Threshold for claims to be insured by third party insurers		250,000
Accrued liabilities for uninsured portion of claims		1,300,000	800,000
Workers compensation auto and general liability claims [Member]
Loss Contingencies [Line Items]
Threshold for claims to be insured by third party insurers		750,000
Accrued liabilities for uninsured portion of claims		$ 2,500,000	$ 1,900,000