Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2015



	Regulatory Assets
In thousands	2015		2014
Current:
Unrealized loss on derivatives⁽¹⁾	$	22,092	$	29,889
Gas costs	8,717		21,794
Environmental costs⁽²⁾	9,270		—
Decoupling⁽³⁾	18,775		7,505
Other⁽⁴⁾	10,324		9,374
Total current	$	69,178	$	68,562
Non-current:
Unrealized loss on derivatives⁽¹⁾	$	3,447	$	3,515
Pension balancing⁽⁵⁾	43,748		32,541
Income taxes	43,049		47,427
Pension and other postretirement benefit liabilities	184,223		201,845
Environmental costs⁽²⁾	76,584		58,859
Gas costs	1,949		5,971
Other⁽⁴⁾	17,711		18,750
Total non-current	$	370,711	$	368,908



	Regulatory Liabilities
In thousands	2015		2014
Current:
Gas costs	$	14,157	$	5,700
Unrealized gain on derivatives⁽¹⁾	2,659		240
Other⁽⁴⁾	13,111		13,165
Total current	$	29,927	$	19,105
Non-current:
Gas costs	$	8,869	$	2,507
Unrealized gain on derivatives⁽¹⁾	27		—
Accrued asset removal costs⁽⁶⁾	327,047		311,238
Other⁽⁴⁾	3,344		3,460
Total non-current	$	339,287	$	317,205