Commitments And Contingencies: Future Purchase Agreement - Related Party (Details) - Wygen I Generating Facility - Purchase Option, Property $ in Millions |
12 Months Ended |
---|---|
Dec. 31, 2017
USD ($)
MW
| |
Unrecorded Unconditional Purchase Obligation [Line Items] | |
Number of Megawatts Capacity Purchased | MW | 60 |
Long-term Contract for Purchase of Electric Power, Date of Contract Expiration | Dec. 31, 2022 |
Asset Purchase Option | $ | $ 2.6 |
Property, Plant and Equipment, Useful Life | 35 years |