Derivative Instruments (Tables)

12 Months Ended

Dec. 31, 2018

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Schedule of Notional Amounts of Outstanding Derivative Positions

The following table presents the absolute notional amounts related to open positions on NW Natural derivative instruments:

	At December 31,
In thousands	2018		2017
Natural gas (in therms):
Financial	408,850		429,100
Physical	472,275		520,268
Foreign exchange	$	6,936	$	7,669

Income Statement Presentation of Derivative Instruments

The following table reflects the income statement presentation for the unrealized gains and losses from NW Natural's derivative instruments, which also represents all derivative instruments at NW Holdings:

	December 31, 2018						December 31, 2017
In thousands	Natural gas commodity			Foreign exchange			Natural gas commodity			Foreign exchange
Benefit (expense) to cost of gas	$	(1,239	)	$	(284	)	$	(26,000	)	$	107
Operating revenues	1,660			—			(1,021		)	—
Amounts deferred to regulatory accounts on balance sheet	(211		)	284			26,665			(107		)
Total gain (loss) in pre-tax earnings	$	210		$	—		$	(356	)	$	—

Table Of Estimated Collateral Calls Table

			Credit Rating Downgrade Scenarios
In thousands	(Current Ratings) A+/A3		BBB+/Baa1		BBB/Baa2		BBB-/Baa3			Specu-lative
With Adequate Assurance Calls	$	—	$	—	$	—	$	(3,940	)	$	(6,059	)
Without Adequate Assurance Calls	—		—		—		(3,940		)	(4,452		)