Significant Accounting Policies (Tables)

3 Months Ended

Mar. 31, 2019

Accounting Policies [Abstract]

Schedule of Regulatory Assets

Amounts deferred as regulatory assets and liabilities were as follows:

	Regulatory Assets
	March 31,				December 31,
In thousands	2019		2018		2018
Current:
Unrealized loss on derivatives(1)	$	2,845	$	17,569	$	12,381
Gas costs	17,927		591		2,873
Environmental costs(2)	5,090		5,818		5,601
Decoupling(3)	3,937		9,578		9,140
Pension balancing(4)	4,955		—		—
Income taxes	2,209		2,218		2,218
Other(5)	9,354		10,126		9,717
Total current	$	46,317	$	45,900	$	41,930
Non-current:
Unrealized loss on derivatives(1)	$	1,161	$	2,355	$	3,025
Pension balancing(4)	50,408		63,940		74,173
Income taxes	17,758		19,267		19,185
Pension and other postretirement benefit liabilities	171,565		175,505		174,993
Environmental costs(2)	66,612		66,730		76,149
Gas costs	8,919		49		9,978
Decoupling(3)	250		2,663		2,545
Other(5)	10,521		12,528		11,738
Total non-current	$	327,194	$	343,037	$	371,786

Schedule of Regulatory Liabilities

	Regulatory Liabilities
	March 31,				December 31,
In thousands	2019		2018		2018
Current:
Gas costs	$	11,126	$	17,798	$	17,182
Unrealized gain on derivatives(1)	7,284		1,120		8,740
Decoupling(3)	2,055		2,501		2,264
Income taxes	7,763		—		—
Other(5)	18,542		13,527		19,250
Total current	$	46,770	$	34,946	$	47,436
Non-current:
Gas costs	$	1,421	$	5,639	$	552
Unrealized gain on derivatives(1)	541		1,148		725
Decoupling(3)	614		1,253		—
Income taxes(6)	202,692		219,795		225,408
Accrued asset removal costs(7)	384,702		365,363		380,464
Other(5)	10,728		7,244		4,411
Total non-current	$	600,698	$	600,442	$	611,560

⁽¹⁾  Unrealized gains or losses on derivatives are non-cash items and therefore do not earn a rate of return or a carrying charge. These amounts are recoverable through NGD rates as part of the annual Purchased Gas Adjustment (PGA) mechanism when realized at settlement.

⁽²⁾  Refer to footnote (3) of the Deferred Regulatory Asset table in Note 16 for a description of environmental costs.

⁽³⁾  This deferral represents the margin adjustment resulting from differences between actual and expected volumes. 

⁽⁴⁾  Refer to Note 9 for information regarding the deferral of pension expenses.

⁽⁵⁾  Balances consist of deferrals and amortizations under approved regulatory mechanisms and typically earn a rate of return or carrying charge.

⁽⁶⁾  This balance represents estimated amounts associated with the Tax Cuts and Jobs Act. See Note 10.

⁽⁷⁾  Estimated costs of removal on certain regulated properties are collected through rates.