Derivative Instruments (Tables)

9 Months Ended

Sep. 30, 2016

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Schedule of Notional Amounts of Outstanding Derivative Positions [Table Text Block]

	September 30,				December 31,
In thousands	2016		2015		2015
Natural gas (in therms):
Financial	537,100		416,075		346,875
Physical	621,230		521,350		404,645
Foreign exchange (in thousands)	$	8,404	$	8,023	$	9,025

Income Statement Presentation of Derivative Instruments [Text Block]

	Three Months Ended September 30,
	2016						2015
In thousands	Natural gas commodity			Foreign exchange			Natural gas commodity			Foreign exchange
Benefit (expense) to cost of gas	$	(8,045	)	$	(52	)	$	(8,415	)	$	(150	)
Operating (loss) revenues	(110		)	—			33			—
Less:
Amounts deferred to regulatory accounts on balance sheet	8,118			52			8,391			150
Total (loss) gain in pre-tax earnings	$	(37	)	$	—		$	9		$	—

	Nine Months Ended September 30,
	2016						2015
In thousands	Natural gas commodity			Foreign exchange			Natural gas commodity			Foreign exchange
Benefit (expense) to cost of gas	$	5,562		$	5		$	(21,876	)	$	(413	)
Operating (loss) revenues	(266		)	—			55			—
Less:
Amounts deferred to regulatory accounts on balance sheet	(5,385		)	(5		)	21,838			413
Total (loss) gain in pre-tax earnings	$	(89	)	$	—		$	17		$	—

Table Of Estimated Collateral Calls Table [Text Block]

			Credit Rating Downgrade Scenarios
In thousands	(Current Ratings) A+/A3		BBB+/Baa1		BBB/Baa2		BBB-/Baa3			Speculative
With Adequate Assurance Calls	$	—	$	—	$	—	$	(1,036	)	$	(1,242	)
Without Adequate Assurance Calls	—		—		—		(1,036		)	181