Acquisitions and Dispositions Disposition (Details) - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 02, 2018	Dec. 31, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Including Discontinued Operation, Consideration			$ 3,100,000
Notes Receivable, Related Parties			7,500,000
Loans Receivable with Fixed Rates of Interest			0.0152
Asset Retirement Obligation	$ 11,929,000		11,738,000
Line of Credit Facility, Maximum Borrowing Capacity		$ 47,000,000
Gain (Loss) on Disposition of Business	(31,457,000)
Business Exit Costs	$ 1,400,000
Maritech [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Asset Retirement Obligation			$ 46,800,000