Property, Plant and Equipment Capital Leases (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Capital Leased Assets [Line Items]
Capital Lease Obligations	$ 77,438	$ 79,551
Capital Leases, Lessee Balance Sheet, Assets by Major Class, Accumulated Depreciation	51,213	46,503
PA Operations [Member]
Capital Leased Assets [Line Items]
Capital Lease Obligations	2,525	1,923
Computer Equipment [Member]
Capital Leased Assets [Line Items]
Capital Lease Obligations	1,979	3,235
jewell ridge pipeline [Member]
Capital Leased Assets [Line Items]
Capital Lease Obligations	66,919
Gas Segment [Member]
Capital Leased Assets [Line Items]
Capital Lease Obligations	$ 6,015	$ 7,474

Amount equal to the present value (the principal) at the beginning of the lease term of minimum lease payments during the lease term (excluding that portion of the payments representing executory costs such as insurance, maintenance, and taxes to be paid by the lessor, together with any profit thereon) net of payments or other amounts applied to the principal through the balance sheet date.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6455398&loc=d3e45280-112737

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 03
-Paragraph 16
-Article 7

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+ References

No definition available.

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- Definition

The total charge for the use of long-lived depreciable assets subject to a lease meeting the criteria for capitalization.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 30
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6455314&loc=d3e45014-112735

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 10
-Section 55
-Paragraph 40
-Subparagraph (Note 2)
-URI http://asc.fasb.org/extlink&oid=6584154&loc=d3e38371-112697

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