Property, Plant and Equipment Capital Leases (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Capital Leased Assets [Line Items]
Capital Lease Obligations	$ 87,055	$ 96,015
Capital Leases, Lessee Balance Sheet, Assets by Major Class, Accumulated Depreciation	49,735	50,371
jewell ridge pipeline [Member]
Capital Leased Assets [Line Items]
Capital Lease Obligations	66,919
Vehicles [Member]
Capital Leased Assets [Line Items]
Capital Lease Obligations	10,207	10,652
Computer Equipment [Member]
Capital Leased Assets [Line Items]
Capital Lease Obligations	$ 9,929	$ 18,444