Description of minimum financial levels (for example, tangible net worth and working capital) and achievement of certain financial ratios (for example, working capital ratio and debt service coverage ratio), and adherence to certain clauses which generally require or restrict certain actions (for example, entering into a debt arrangement with equal or greater seniority, and selling or discontinuing a certain business segment or material subsidiary) to be in compliance with the covenant clauses of the debt agreement. May also include a discussion of the adverse consequences that would result if the entity violates or fails to satisfy the covenants.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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The cash inflow during the period from additional borrowings in aggregate debt. Includes proceeds from short-term and long-term debt.

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Indebtedness divided by net capital.

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The cash outflow during the period from the repayment of aggregate short-term and long-term debt. Excludes payment of capital lease obligations.

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The remaining balance of debt issuance expenses that were capitalized and are being amortized against income over the lives of the respective bond issues. This does not include the amounts capitalized as part of the cost of the utility plant or asset.

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Long-Term Debt (Details) $ in Thousands	3 Months Ended	6 Months Ended
Long-Term Debt (Details) $ in Thousands	Jun. 30, 2020 USD ($)	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)
Debt Instrument [Line Items]
Long-term Debt	$ 954,096	$ 954,096	$ 910,397	$ 881,064
Unamortized debt issuance costs	$ 7,688	$ 7,688	6,435	5,712
Ratio of Indebtedness to Net Capital	0.573	0.573
Northwest Natural Gas Company [Member]
Debt Instrument [Line Items]
Long-term Debt	$ 917,012	$ 917,012	873,306	843,988
Unamortized debt issuance costs	$ 7,688	$ 7,688	6,394	$ 5,712
Weighted average interest rate	4.597%	4.597%
Ratio of Indebtedness to Net Capital	0.560	0.560
Northwest Natural Gas Company [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Stated interest rate	2.822%	2.822%
Northwest Natural Gas Company [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Stated interest rate	9.05%	9.05%
Note 3.60 Series Due 2050 [Member] \| Northwest Natural Gas Company [Member]
Debt Instrument [Line Items]
Stated interest rate	3.60%	3.60%
Proceeds from Issuance of Debt		$ 150,000
Note 537 Series Due 2020 [Member] \| Northwest Natural Gas Company [Member]
Debt Instrument [Line Items]
Stated interest rate	5.37%	5.37%
Repayments of Debt	$ 75,000
Two-year Term Loan Due 2021 [Member]
Debt Instrument [Line Items]
Stated interest rate	0.73%	0.73%
Proceeds from Issuance of Debt			$ 35,000
Debt Instrument, Covenant Description		requires NW Holdings to maintain a consolidated indebtedness to total capitalization ratio of 70% or less