Investments (Narrative) (Details)	12 Months Ended
	Dec. 31, 2017 USD ($) a facility	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Schedule of Equity Method Investments
Equity method investment	$ 162,000	$ 4,031,000
Equity method investments, impairment		0	$ 0
Equity in income (loss) of nonconsolidated investments	$ 6,000	(1,290,000)	(413,000)
Lb Pipe Coupling Products Llc
Schedule of Equity Method Investments
Equity method investment ownership percentage	45.00%
Equity method investment	$ 3,875,000	3,902,000
Impairment of long lived assets to be disposed of	413,000
Due from joint venture	1,235,000
Equity in income (loss) of nonconsolidated investments	$ 386,000	(1,345,000)	$ (410,000)
Lb Pipe Coupling Products Llc | Capital Leased Land
Schedule of Equity Method Investments
Area of land | a	5
Number of facilities | facility	2
Capital lease length of renewal term	5 years 6 months
Monthly rent	$ 17,000
Balloon payment	$ 488,000
Lb Pipe Coupling Products Llc | Third Party
Schedule of Equity Method Investments
Equity method investment ownership percentage	45.00%
LB Pipe JV
Schedule of Equity Method Investments
Maximum lending capacity	$ 1,350,000
Other equity investments
Schedule of Equity Method Investments
Equity method investment	162,000	$ 129,000
Fair Value | Lb Pipe Coupling Products Llc
Schedule of Equity Method Investments
Equity method investment	3,875,000
Carrying value | Lb Pipe Coupling Products Llc
Schedule of Equity Method Investments
Equity method investment	$ 4,288,000