Derivative Instruments (Tables)

9 Months Ended

Sep. 30, 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 derivative instruments:

	September 30,				December 31,
In thousands	2018		2017		2017
Natural gas (in therms):
Financial	513,850		521,080		429,100
Physical	760,925		750,650		520,268
Foreign exchange	$	7,184	$	6,933	$	7,669

Income Statement Presentation of Derivative Instruments

The following table reflects the income statement presentation for the unrealized gains and losses from derivative instruments:

	Three Months Ended September 30,
	2018						2017
In thousands	Natural gas commodity			Foreign exchange			Natural gas commodity			Foreign exchange
Benefit (expense) to cost of gas	$	4,473		$	210		$	(2,566	)	$	51
Operating revenues	(286		)	—			28			—
Amounts deferred to regulatory accounts on balance sheet	(4,285		)	(210		)	2,548			(51		)
Total gain (loss) in pre-tax earnings	$	(98	)	$	—		$	10		$	—

	Nine Months Ended September 30,
	2018					2017
In thousands	Natural gas commodity			Foreign exchange		Natural gas commodity			Foreign exchange
Benefit (expense) to cost of gas	$	1,384		$	—	$	(19,081	)	$	275
Operating revenues	(122		)	—		(1,249		)	—
Amounts deferred to regulatory accounts on balance sheet	(1,305		)	—		19,895			(275		)
Total gain (loss) in pre-tax earnings	$	(43	)	$	—	$	(435	)	$	—

Table of Estimated Collateral Calls Table

Based upon current commodity financial swap and option contracts outstanding, which reflect unrealized losses of $9.7 million at September 30, 2018, we have estimated the level of collateral demands, with and without potential adequate assurance calls, using current gas prices and various credit downgrade rating scenarios for NW Natural as follows:

			Credit Rating Downgrade Scenarios
In thousands	(Current Ratings) A+/A3		BBB+/Baa1		BBB/Baa2		BBB-/Baa3			Speculative
With Adequate Assurance Calls	$	—	$	—	$	—	$	(2,587	)	$	(7,023	)
Without Adequate Assurance Calls	—		—		—		(2,587		)	(4,730		)