Summary of Significant Accounting Policies (tables)

12 Months Ended

Dec. 31, 2013

Accounting Policies [Abstract]

Schedule of Regulatory Assets [Table Text Block]

	Regulatory Assets
In thousands	2013		2012
Current:
Unrealized loss on derivatives(1)	$	1,891	$	10,796
Other(2)	20,744		41,652
Total current	$	22,635	$	52,448
Non-current:
Unrealized loss on derivatives(1)	$	615	$	578
Pension balancing(3)	25,713		14,727
Income tax asset	51,814		55,879
Pension and other postretirement benefit liabilities(3)	125,855		182,688
Environmental costs(4)	148,389		121,144
Other(2)	17,217		7,239
Total non-current	$	369,603	$	382,255

Schedule of Regulatory Liabilities [Table Text Block]

	Regulatory Liabilities
In thousands	2013		2012
Current:
Gas costs	$	7,510	$	9,100
Unrealized gain on derivatives(1)	5,290		1,950
Other(2)	15,535		9,742
Total current	$	28,335	$	20,792
Non-current:
Gas costs	$	2,172	$	—
Unrealized gain on derivatives(1)	1,880		3,639
Accrued asset removal costs	296,294		281,213
Other(2)	3,139		3,261
Total non-current	$	303,485	$	288,113