Discontinued Operations (Details Textual) - USD ($)	1 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of a business		$ 0	$ 0	$ 89,766,000
Gain from disposal of discontinued operations before income taxes		0	0	33,974,000
Gain from disposal of discontinued operations, net of tax		0	$ 0	22,117,000
Environmental services [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from divestiture of businesses	$ 100,000,000
Proceeds from sale of a business	89,800,000
Gain from disposal of discontinued operations before income taxes				34,000,000
Gain from disposal of discontinued operations, net of tax				22,100,000
Ecoserv [Member] | Environmental services [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Escrow deposit	8,000,000			8,000,000
Released 9 months from closing date | Ecoserv [Member] | Environmental services [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Escrow deposit	$ 4,000,000			4,000,000
Released 18 months from closing date | Ecoserv [Member] | Environmental services [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Escrow deposit		$ 4,000,000.0		$ 4,000,000