Accrued Liabilities and Deferred Credits - Narrative (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2006 a	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Deferred revenue		$ 15,222	$ 15,309
Accruals for legal fees and expenses related to the SEC investigation		1,200
Florida Department of Transportation
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Deferred revenue		$ 12,500	$ 12,500
Acres of land sold | a	3,900