Investments in and Loans to Joint Ventures (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Carrying amount of investments in and loans to joint ventures
Total investments in and loans to joint ventures	$ 21,454	$ 22,571
Ohio Castings [Member]
Carrying amount of investments in and loans to joint ventures
Total investments in and loans to joint ventures	5,885	6,202
Axis [Member]
Carrying amount of investments in and loans to joint ventures
Total investments in and loans to joint ventures	$ 15,569	$ 16,369

Total investments in (A) an entity in which the entity has significant influence, but does not have control, (B) subsidiaries that are not required to be consolidated and are accounted for using the equity and or cost method, and (C) an entity in which the reporting entity shares control of the entity with another party or group. Includes long-term advances receivable from a party that is affiliated with the reporting entity by means of direct or indirect ownership.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.12)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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