Derivative Instruments (Tables)

6 Months Ended

Jun. 30, 2015

Derivative Instruments, Gain (Loss) [Line Items]

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	$	—	$	—	$	—	$	—	$	12,709
Without Adequate Assurance Calls	—		—		—		—		8,767

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

	June 30,				December 31,
In thousands	2015		2014		2014
Natural gas (in therms):
Financial	350,250		297,925		287,475
Physical	296,250		241,150		420,980
Foreign exchange	$	7,920	$	10,844	$	12,230

Income Statement Presentation of Derivative Instruments [Text Block]

	Three Months Ended June 30,
	2015						2014
In thousands	Natural gas commodity			Foreign currency			Natural gas commodity			Foreign currency
Benefit (expense) to cost of gas	$	10,020		$	478		$	(5,379	)	$	454
Operating revenues	(616		)	—			—			—
Less:
Amounts deferred to regulatory accounts on the balance sheet	(9,618		)	(478		)	5,223			(454		)
Total loss in pre-tax earnings	$	(214	)	$	—		$	(156	)	$	—

	Six Months Ended June 30,
	2015						2014
In thousands	Natural gas commodity			Foreign currency			Natural gas commodity			Foreign currency
(Expense) benefit to cost of gas	$	(13,461	)	$	(263	)	$	10,533		$	179
Operating revenues	22			—			—			—
Less:
Amounts deferred to regulatory accounts on the balance sheet	13,447			263			(10,652		)	(179		)
Total gain (loss) in pre-tax earnings	$	8		$	—		$	(119	)	$	—