Discontinued Operations (Cash Flow Information) (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Net Cash Provided by (Used in) Discontinued Operations [Abstract]
Net cash provided by discontinued operating activities		$ 0	$ 12,753
Hereford Production Facility \| Discontinued Operations, Disposed of by Sale
Net Cash Provided by (Used in) Discontinued Operations [Abstract]
Net cash provided by discontinued operating activities	$ 8,462		12,753
Net cash used in discontinued investing activities	$ (2,807)		$ (3,762)

Amount of cash inflow (outflow) of investing activities of discontinued operations. Investing activity cash flows include making and collecting loans and acquiring and disposing of debt or equity instruments and property, plant, and equipment and other productive assets.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 24
-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3521-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 5B
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=51717284&loc=SL51721673-107760

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration