Investments	3 Months Ended
Mar. 31, 2013
Investments [Abstract]
Investments Disclosure [Text Block]	11. INVESTMENTS Equity Method Investments Palomar, a wholly-owned subsidiary of PGH, is pursuing the development of a new gas transmission pipeline that would provide an interconnection with our utility distribution system. PGH is owned 50% by NWN Energy and 50% by TransCanada American Investments Ltd., an indirect wholly-owned subsidiary of TransCanada Corporation. Variable Interest Entity (VIE) Analysis PGH is a development stage VIE. As of March 31, 2013, there were no changes to our VIE analysis and, as such, we continue to report Palomar under equity method accounting based on the determination that we are not the primary beneficiary of PGH’s activities, as defined by the authoritative guidance related to consolidations, due to the fact that we have a 50% share and there are no stipulations that allow disproportionate influence over the entity. Our investment in PGH and Palomar are included in other investments on our balance sheet. Our maximum loss exposure related to PGH is limited to our equity investment balance, less our share of any cash or other assets available to us as a 50% owner. Impairment Analysis Our investments in nonconsolidated entities accounted for under the equity method are reviewed for impairment at each reporting period and following updates to our corporate planning assumptions. When it is determined that a loss in value is other than temporary, a charge is recognized for the difference between the investment’s carrying value and its estimated fair value. Fair value is based on quoted market prices when available, or on the present value of expected future cash flows. Differing assumptions could affect the timing and amount of a charge recorded in any period. There have been no significant changes in carrying value or estimated fair value since year end. Our investment balance in PGH was $13.4 million at March 31, 2013. PGH is continuing to work on development of commercial support for the project. A new Federal Energy Regulatory Commission (FERC) certificate application is expected to be filed to reflect a revised scope based on regional needs for the proposed pipeline. If we learn that the project is not viable or will not go forward in the future, we could be required to recognize a maximum charge of up to approximately $13.2 million based on the current amount of our equity investment, net of cash, and working capital at PGH. We will continue to monitor and update our impairment analysis as required. See Note 12 in our 2012 Form 10-K for more detail. Other Investments Other investments include financial investments in life insurance policies, which are accounted for at fair value. See Note 12 in the 2012 Form 10-K for more detail on other investments.

11. INVESTMENTS

Equity Method Investments

Palomar, a wholly-owned subsidiary of PGH, is pursuing the development of a new gas transmission pipeline that would provide an interconnection with our utility distribution system. PGH is owned 50% by NWN Energy and 50% by TransCanada American Investments Ltd., an indirect wholly-owned subsidiary of TransCanada Corporation.

Variable Interest Entity (VIE) Analysis

PGH is a development stage VIE. As of March 31, 2013, there were no changes to our VIE analysis and, as such, we continue to report Palomar under equity method accounting based on the determination that we are not the primary beneficiary of PGH’s activities, as defined by the authoritative guidance related to consolidations, due to the fact that we have a 50% share and there are no stipulations that allow disproportionate influence over the entity. Our investment in PGH and Palomar are included in other investments on our balance sheet. Our maximum loss exposure related to PGH is limited to our equity investment balance, less our share of any cash or other assets available to us as a 50% owner.

Impairment Analysis

Our investments in nonconsolidated entities accounted for under the equity method are reviewed for impairment at each reporting period and following updates to our corporate planning assumptions. When it is determined that a loss in value is other than temporary, a charge is recognized for the difference between the investment’s carrying value and its estimated fair value. Fair value is based on quoted market prices when available, or on the present value of expected future cash flows. Differing assumptions could affect the timing and amount of a charge recorded in any period. There have been no significant changes in carrying value or estimated fair value since year end.

Our investment balance in PGH was $13.4 million at March 31, 2013. PGH is continuing to work on development of commercial support for the project. A new Federal Energy Regulatory Commission (FERC) certificate application is expected to be filed to reflect a revised scope based on regional needs for the proposed pipeline. If we learn that the project is not viable or will not go forward in the future, we could be required to recognize a maximum charge of up to approximately $13.2 million based on the current amount of our equity investment, net of cash, and working capital at PGH. We will continue to monitor and update our impairment analysis as required. See Note 12 in our 2012 Form 10-K for more detail.

Other Investments

Other investments include financial investments in life insurance policies, which are accounted for at fair value. See Note 12 in the 2012 Form 10-K for more detail on other investments.