Discontinued Operations - Operating Results for Discontinued Operations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net loss	$ 0	$ 0	$ (3,847)
Discontinued Operations, Liquidated | Bayou Welding Works
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenues			0
Gross profit (loss)			(67)
Operating expenses			(5,941)
Operating loss			(6,008)
Other income (expense)			(74)
Loss before tax benefits			(6,082)
Tax benefits			2,235
Net loss			$ (3,847)