Derivative Instruments (tables)

9 Months Ended

Sep. 30, 2013

Summary of Derivative Instruments [Abstract]

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

	September 30,				December 31,
In thousands	2013		2012		2012
Open position absolute notional amount:
Natural gas volumes (therms)	527,700		460,470		395,820
Foreign exchange	$	13,862	$	13,775	$	13,231

Income Statement Presentation of Derivative Instruments [Text Block]

	Three Months Ended
	September 30, 2013						September 30, 2012
In thousands	Natural gas commodity			Foreign currency			Natural gas commodity			Foreign currency
Cost of sales increase	$	2,422		$	—		$	22,558		$	—
Other comprehensive income	—			502			—			273
Less:
Amounts deferred to regulatory accounts	(2,433		)	(502		)	(22,558		)	(273		)
Total loss in pre-tax earnings	$	(11	)	$	—		$	—		$	—

	Nine Months Ended
	September 30, 2013						September 30, 2012
In thousands	Natural gas commodity			Foreign currency			Natural gas commodity			Foreign currency
Cost of sales decrease	$	(6,534	)	$	—		$	(5,556	)	$	—
Other comprehensive income (loss)	—			(11		)	—			162
Less:
Amounts deferred to regulatory accounts	6,599			11			5,556			(162		)
Total gain in pre-tax earnings	$	65		$	—		$	—		$	—

Credit Rating Downgrade Scenarios [Text Block]

			Credit Rating Downgrade Scenarios
In thousands	(Current Ratings) A+/A3		BBB+/Baa1		BBB/Baa2		BBB-/Baa3		Speculative
With Adequate Assurance Calls	$	—	$	—	$	—	$	—	$	4,081
Without Adequate Assurance Calls	—		—		—		—		4,212