Fair Value (Tables)

12 Months Ended

Dec. 31, 2018

Fair Value Measurement Inputs and Valuation Techniques [Table Text Block]

The following table presents the quantitative information which was used to estimate the fair values of the Level 3 assets and liabilities above as of December 31, 2018 (dollars in thousands):



	Fair Value (Net) at
	December 31, 2018			Valuation Technique	Unobservable Input	Range
Power exchange agreement	$	(2,488	)	Surrogate facility	O&M charges	$40.05-$52.59/MWh (1)
				pricing	Transaction volumes	173,465 MWhs
Natural gas exchange	(2,774		)	Internally derived	Forward purchase prices	$1.44 - $1.88/mmBTU
agreement				weighted-average	Forward sales prices	$1.47 - $3.34/mmBTU
				cost of gas	Purchase volumes	115,000 - 310,000 mmBTUs
					Sales volumes	60,000 - 310,000 mmBTUs

(1) The average O&M charges for the delivery year beginning in November 2018 are $45.61 per MWh.

Carrying Value and Estimated Fair Value of Financial Instruments



	2018				2017
	Carrying Value		Estimated Fair Value		Carrying Value		Estimated Fair Value
Long-term debt (Level 2)	$	1,053,500	$	1,142,292	$	951,000	$	1,067,783
Long-term debt (Level 3)	767,000		734,742		767,000		810,598
Snettisham capital lease obligation (Level 3)	57,210		55,600		59,745		61,700
Long-term debt to affiliated trusts (Level 3)	51,547		38,145		51,547		41,882

Fair Value of Assets And Liabilities Measured on Recurring Basis



	Level 1		Level 2		Level 3		Counterparty and Cash Collateral Netting (1)			Total
December 31, 2018
Assets:
Energy commodity derivatives	$	—	$	36,252	$	—	$	(35,982	)	$	270
Level 3 energy commodity derivatives:
Natural gas exchange agreements	—		—		31		(31		)	—
Interest rate swap derivatives	—		10,566		—		(440		)	10,126
Deferred compensation assets:
Mutual Funds:
Fixed income securities (2)	1,745		—		—		—			1,745
Equity securities (2)	6,157		—		—		—			6,157
Total	$	7,902	$	46,818	$	31	$	(36,453	)	$	18,298
Liabilities:
Energy commodity derivatives	$	—	$	89,283	$	—	$	(87,199	)	$	2,084
Level 3 energy commodity derivatives:
Natural gas exchange agreement	—		—		2,805		(31		)	2,774
Power exchange agreement	—		—		2,488		—			2,488
Power option agreement	—		—		1		—			1
Foreign currency exchange derivatives	—		45		—		—			45
Interest rate swap derivatives	—		7,831		—		(970		)	6,861
Total	$	—	$	97,159	$	5,294	$	(88,200	)	$	14,253

The following table discloses by level within the fair value hierarchy the Company’s assets and liabilities measured and reported on the Consolidated Balance Sheets as of December 31, 2017 at fair value on a recurring basis (dollars in thousands):



	Level 1		Level 2		Level 3		Counterparty and Cash Collateral Netting (1)			Total
December 31, 2017
Assets:
Energy commodity derivatives	$	—	$	43,814	$	—	$	(42,550	)	$	1,264
Level 3 energy commodity derivatives:
Natural gas exchange agreement	—		—		183		(183		)	—
Foreign currency exchange derivatives	—		32		—		(1		)	31
Interest rate swap derivatives	—		7,477		—		(2,574		)	4,903
Deferred compensation assets:
Mutual Funds:
Fixed income securities (2)	1,638		—		—		—			1,638
Equity securities (2)	6,631		—		—		—			6,631
Total	$	8,269	$	51,323	$	183	$	(45,308	)	$	14,467



	Level 1		Level 2		Level 3		Counterparty and Cash Collateral Netting (1)			Total
Liabilities:
Energy commodity derivatives	$	—	$	71,342	$	—	$	(69,988	)	$	1,354
Level 3 energy commodity derivatives:
Natural gas exchange agreement	—		—		3,347		(183		)	3,164
Power exchange agreement	—		—		13,245		—			13,245
Power option agreement	—		—		19		—			19
Foreign currency exchange derivatives	—		1		—		(1		)	—
Interest rate swap derivatives	—		73,513		—		(37,544		)	35,969
Total	$	—	$	144,856	$	16,611	$	(107,716	)	$	53,751


(1)	The Company is permitted to net derivative assets and derivative liabilities with the same counterparty when a legally enforceable master netting agreement exists. In addition, the Company nets derivative assets and derivative liabilities against any payables and receivables for cash collateral held or placed with these same counterparties.


(2)	These assets are included in other property and investments-net and other non-current assets on the Consolidated Balance Sheets.

Reconciliation for All Assets Measured At Fair Value on a Recurring Basis Using Significant Unobservable Inputs (Level 3)



	Natural Gas Exchange Agreement			Power Exchange Agreement			Total
Year ended December 31, 2018:
Balance as of January 1, 2018	$	(3,164	)	$	(13,245	)	$	(16,409	)
Total gains or (losses) (realized/unrealized):
Included in regulatory assets/liabilities (1)	326			5,027			5,353
Settlements	64			5,730			5,794
Ending balance as of December 31, 2018 (2)	$	(2,774	)	$	(2,488	)	$	(5,262	)
Year ended December 31, 2017:
Balance as of January 1, 2017	$	(5,885	)	$	(13,449	)	$	(19,334	)
Total gains or (losses) (realized/unrealized):
Included in regulatory assets/liabilities (1)	3,292			(7,674		)	(4,382		)
Settlements	(571		)	7,878			7,307
Ending balance as of December 31, 2017 (2)	$	(3,164	)	$	(13,245	)	$	(16,409	)



	Natural Gas Exchange Agreement			Power Exchange Agreement			Total
Year ended December 31, 2016:
Balance as of January 1, 2016	$	(5,039	)	$	(21,961	)	$	(27,000	)
Total gains or (losses) (realized/unrealized):
Included in regulatory assets/liabilities (1)	259			400			659
Settlements	(1,105		)	8,112			7,007
Ending balance as of December 31, 2016 (2)	$	(5,885	)	$	(13,449	)	$	(19,334	)


(1)	All gains and losses are included in other regulatory assets and liabilities. There were no gains and losses included in either net income or other comprehensive income during any of the periods presented in the table above.


(2)	There were no purchases, issuances or transfers from other categories of any derivatives instruments during the periods presented in the table above.