Investments (Narrative) (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017 USD ($) a facility	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($) a facility	Jun. 30, 2016 USD ($)	Dec. 31, 2016 USD ($)
Schedule of Equity Method Investments [Line Items]
Equity investments	$ 3,976		$ 3,976		$ 4,031
Equity in income (loss) of nonconsolidated investments	145	$ (487)	$ (55)	$ (683)
Variable Interest Entity, Not Primary Beneficiary, Aggregated Disclosure
Schedule of Equity Method Investments [Line Items]
Variable interest entity, methodology for determining whether entity is primary beneficiary			Under applicable guidance for variable interest entities in ASC 810, "Consolidation," the Company determined that the LB Pipe JV is a variable interest entity. The Company concluded that it is not the primary beneficiary of the variable interest entity, as the Company does not have a controlling financial interest and does not have the power to direct the activities that most significantly impact the economic performance of the LB Pipe JV. Accordingly, the Company concluded that the equity method of accounting remains appropriate.
LB Pipe & Coupling Products, LLC
Schedule of Equity Method Investments [Line Items]
Equity investments	$ 3,853		$ 3,853		3,902
Equity method investment, ownership percentage	45.00%		45.00%
Equity method investment, description of principal activities			The Company is a member of a joint venture, LB Pipe & Coupling Products, LLC ("LB Pipe JV"), in which it maintains a 45% ownership interest. The LB Pipe JV manufactures, markets, and sells various precision coupling products for the energy, utility, and construction markets and is scheduled to terminate on June 30, 2019.
Equity in income (loss) of nonconsolidated investments	$ 150	$ (476)	$ (48)	$ (725)
Line of credit, maximum lending capacity					1,350
Due from joint ventures, current					$ 1,235
LB Pipe & Coupling Products, LLC | Capital Leased Land
Schedule of Equity Method Investments [Line Items]
Area of land | a	5		5
Capital leased assets, number of units | facility	2		2
Capital lease length of renewal term			5 years 6 months
Capital Leases, monthly rent			$ 17
Capital leases balloon payment in direct financing leases	$ 488		$ 488
LB Pipe & Coupling Products, LLC | Other Joint Venture Member
Schedule of Equity Method Investments [Line Items]
Equity method investment, ownership percentage	45.00%		45.00%		45.00%
Other equity investments
Schedule of Equity Method Investments [Line Items]
Equity investments	$ 123		$ 123		$ 129