Regulatory assets and liabilities (Tables)

12 Months Ended

Dec. 31, 2020

Regulatory Assets and Liabilities Disclosure [Abstract]

Regulatory assets

The following table summarizes the individual components of unamortized regulatory assets and liabilities as of December 31:

	Estimated Recovery or Refund Period	*	2020		2019
			(In thousands)
Regulatory assets:
Current:
Natural gas costs recoverable through rate adjustments	Up to 1 year		$	42,481	$	42,823
Cost recovery mechanisms	Up to 1 year		10,645		6,288
Conservation programs	Up to 1 year		7,117		6,963
Other	Up to 1 year		8,284		7,539
			68,527		63,613
Noncurrent:
Pension and postretirement benefits	**		155,942		157,069
Plant costs/asset retirement obligations	Over plant lives		71,740		66,000
Plant to be retired	-		65,919		32,931
Manufactured gas plant sites remediation	-		26,429		15,126
Natural gas costs recoverable through rate adjustments	Up to 2 years		21,539		46,381
Cost recovery mechanisms	Up to 10 years		16,245		13,108
Taxes recoverable from customers	Over plant lives		10,785		11,486
Long-term debt refinancing costs	Up to 40 years		4,426		4,286
Other	Up to 18 years		6,356		7,397
			379,381		353,784
Total regulatory assets			$	447,908	$	417,397
Regulatory liabilities:
Current:
Natural gas costs refundable through rate adjustments	Up to 1 year		$	18,565	$	23,825
Electric fuel and purchased power deferral	Up to 1 year		3,667		5,824
Taxes refundable to customers	Up to 1 year		3,557		3,472
Other	Up to 1 year		5,661		9,814
			31,450		42,935
Noncurrent:
Taxes refundable to customers	Over plant lives		227,850		246,034
Plant removal and decommissioning costs	Over plant lives		167,171		173,722
Pension and postretirement benefits	**		16,989		18,065
Other	Up to 21 years		16,065		9,549
			428,075		447,370
Total regulatory liabilities			$	459,525	$	490,305
Net regulatory position			$	(11,617)	$	(72,908)

*Estimated recovery or refund period for amounts currently being recovered or refunded in rates to customers.

**    Recovered as expense is incurred or cash contributions are made.

Regulatory liabilities

The following table summarizes the individual components of unamortized regulatory assets and liabilities as of December 31:

	Estimated Recovery or Refund Period	*	2020		2019
			(In thousands)
Regulatory assets:
Current:
Natural gas costs recoverable through rate adjustments	Up to 1 year		$	42,481	$	42,823
Cost recovery mechanisms	Up to 1 year		10,645		6,288
Conservation programs	Up to 1 year		7,117		6,963
Other	Up to 1 year		8,284		7,539
			68,527		63,613
Noncurrent:
Pension and postretirement benefits	**		155,942		157,069
Plant costs/asset retirement obligations	Over plant lives		71,740		66,000
Plant to be retired	-		65,919		32,931
Manufactured gas plant sites remediation	-		26,429		15,126
Natural gas costs recoverable through rate adjustments	Up to 2 years		21,539		46,381
Cost recovery mechanisms	Up to 10 years		16,245		13,108
Taxes recoverable from customers	Over plant lives		10,785		11,486
Long-term debt refinancing costs	Up to 40 years		4,426		4,286
Other	Up to 18 years		6,356		7,397
			379,381		353,784
Total regulatory assets			$	447,908	$	417,397
Regulatory liabilities:
Current:
Natural gas costs refundable through rate adjustments	Up to 1 year		$	18,565	$	23,825
Electric fuel and purchased power deferral	Up to 1 year		3,667		5,824
Taxes refundable to customers	Up to 1 year		3,557		3,472
Other	Up to 1 year		5,661		9,814
			31,450		42,935
Noncurrent:
Taxes refundable to customers	Over plant lives		227,850		246,034
Plant removal and decommissioning costs	Over plant lives		167,171		173,722
Pension and postretirement benefits	**		16,989		18,065
Other	Up to 21 years		16,065		9,549
			428,075		447,370
Total regulatory liabilities			$	459,525	$	490,305
Net regulatory position			$	(11,617)	$	(72,908)

*Estimated recovery or refund period for amounts currently being recovered or refunded in rates to customers.

**    Recovered as expense is incurred or cash contributions are made.