Revenue and Related Costs (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2017	Mar. 31, 2016
Oxide plant lease	$ 1,644	$ 1,463
Lease related costs	537	474
Oxide Plant
Oxide plant lease	1,600	1,500
Lease related costs	$ 500	$ 500

The total amount of revenue recognized for the period from operating leases, including minimum lease revenue, contingent revenue, percentage revenue and sublease revenue.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 20
-Section 25
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=7501430&loc=d3e39896-112707

Name:	us-gaap_OperatingLeasesIncomeStatementLeaseRevenue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration