Regulatory Assets and Liabilities (Tables)

9 Months Ended

Sep. 30, 2016

Regulatory Assets and Liabilities Disclosure [Abstract]

Schedule of amount of regulatory assets and liabilities

	September 30, 2016						Remaining Recovery/
(in thousands)	Current		Long-Term		Total		Refund Period
Regulatory Assets:
Prior Service Costs and Actuarial Losses on Pensions and Other Postretirement Benefits1	$	7,439	$	94,671	$	102,110	see below
Deferred Marked-to-Market Losses1		4,063		7,483		11,546	51 months
Conservation Improvement Program Costs and Incentives2		4,286		3,079		7,365	24 months
Accumulated ARO Accretion/Depreciation Adjustment1		—		6,031		6,031	asset lives
Big Stone II Unrecovered Project Costs – Minnesota1		619		2,444		3,063	55 months
North Dakota Renewable Resource Rider Accrued Revenues2		1,608		826		2,434	18 months
Debt Reacquisition Premiums1		349		1,278		1,627	192 months
Deferred Income Taxes1		—		1,157		1,157	asset lives
Minnesota Deferred Rate Case Expenses Subject to Recovery1		748		—		748	12 months
Big Stone II Unrecovered Project Costs – South Dakota2		101		567		668	80 months
North Dakota Transmission Cost Recovery Rider Accrued Revenues2		—		544		544	27 months
MISO Schedule 26/26A Transmission Cost Recovery Rider True-up2		474		43		517	27 months
South Dakota Transmission Cost Recovery Rider Accrued Revenues2		225		—		225	12 months
Minnesota Renewable Resource Rider Accrued Revenues2		46		—		46	12 months
Total Regulatory Assets	$	19,958	$	118,123	$	138,081
Regulatory Liabilities:
Accumulated Reserve for Estimated Removal Costs – Net of Salvage	$	—	$	77,603		77,603	asset lives
Refundable Fuel Clause Adjustment Revenues		2,301		—		2,301	12 months
North Dakota Transmission Cost Recovery Rider Accrued Refund		638		758		1,396	24 months
Minnesota Transmission Cost Recovery Rider Accrued Refund		1,356		—		1,356	12 months
Revenue for Rate Case Expenses Subject to Refund – Minnesota		712		385		1,097	19 months
Deferred Income Taxes		—		918		918	asset lives
Minnesota Environmental Cost Recovery Rider Accrued Refund		370		—		370	12 months
South Dakota Environmental Cost Recovery Rider Accrued Refund		296		—		296	12 months
North Dakota Environmental Cost Recovery Rider Accrued Refund		256		—		256	12 months
Other		5		91		96	207 months
MISO Schedule 26/26A Transmission Cost Recovery Rider True-up		—		80		80	27 months
Total Regulatory Liabilities	$	5,934	$	79,835	$	85,769
Net Regulatory Asset Position	$	14,024	$	38,288	$	52,312

¹Costs subject to recovery without a rate of return.

²Amount eligible for recovery under an alternative revenue program which includes an incentive or rate of return.

	December 31, 2015						Remaining Recovery/
(in thousands)	Current		Long-Term		Total		Refund Period
Regulatory Assets:
Prior Service Costs and Actuarial Losses on Pensions and Other Postretirement Benefits1	$	7,439	$	99,293	$	106,732	see below
Deferred Marked-to-Market Losses1		4,063		10,530		14,593	60 months
Conservation Improvement Program Costs and Incentives2		4,411		4,266		8,677	18 months
Accumulated ARO Accretion/Depreciation Adjustment1		—		5,672		5,672	asset lives
Big Stone II Unrecovered Project Costs – Minnesota1		942		2,620		3,562	84 months
Debt Reacquisition Premiums1		351		1,539		1,890	201 months
Deferred Income Taxes1		—		1,455		1,455	asset lives
North Dakota Renewable Resource Rider Accrued Revenues2		—		1,266		1,266	15 months
MISO Schedule 26/26A Transmission Cost Recovery Rider True-up2		698		355		1,053	24 months
Big Stone II Unrecovered Project Costs – South Dakota2		100		643		743	89 months
Minnesota Transmission Cost Recovery Rider Accrued Revenues2		576		—		576	12 months
Minnesota Deferred Rate Case Expenses Subject to Recovery1		291		—		291	12 months
Minnesota Renewable Resource Rider Accrued Revenues2		—		68		68	see below
South Dakota Transmission Cost Recovery Rider Accrued Revenues2		33		—		33	12 months
Total Regulatory Assets	$	18,904	$	127,707	$	146,611
Regulatory Liabilities:
Accumulated Reserve for Estimated Removal Costs – Net of Salvage	$	—	$	74,948	$	74,948	asset lives
Refundable Fuel Clause Adjustment Revenues		1,834		—		1,834	12 months
Revenue for Rate Case Expenses Subject to Refund – Minnesota		—		1,279		1,279	see below
Deferred Income Taxes		—		1,110		1,110	asset lives
Minnesota Environmental Cost Recovery Rider Accrued Refund		777		—		777	12 months
North Dakota Environmental Cost Recovery Rider Accrued Refund		321		—		321	12 months
South Dakota Environmental Cost Recovery Rider Accrued Refund		185		—		185	12 months
North Dakota Transmission Cost Recovery Rider Accrued Refund		132		—		132	12 months
Deferred Gain on Sale of Utility Property – Minnesota Portion		5		95		100	216 months
North Dakota Renewable Resource Rider Accrued Refund		68		—		68	12 months
Total Regulatory Liabilities	$	3,322	$	77,432	$	80,754
Net Regulatory Asset Position	$	15,582	$	50,275	$	65,857

 ¹Costs subject to recovery without a rate of return.

²Amount eligible for recovery under an alternative revenue program which includes an incentive or rate of return.