Derivative Instruments (tables)

12 Months Ended

Dec. 31, 2014

Summary of Derivative Instruments [Abstract]

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

	At December 31,
In thousands	2014		2013
Natural gas (in therms):
Financial	287,475		389,225
Physical	420,980		552,500
Foreign exchange	$	12,230	$	15,002

Income Statement Presentation of Derivative Instruments [Text Block]

	December 31, 2014						December 31, 2013
In thousands	Natural gas commodity			Foreign exchange			Natural gas commodity			Foreign exchange
Benefit (expense) to cost of gas	$	(32,784	)	$	(382	)	$	4,985		$	(300	)
Less:
Amounts deferred to regulatory accounts on balance sheet	32,782			382			(4,964		)	300
Total gain (loss) in pre-tax earnings	$	(2	)	$	—		$	21		$	—

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	$	—	$	—	$	4	$	2,504	$	27,150
Without Adequate Assurance Calls	—		—		—		—		19,646