Fair Value (Tables)

9 Months Ended

Sep. 30, 2018

Fair Value Inputs, Liabilities, Quantitative Information [Line Items]

Fair Value Inputs, Liabilities, Quantitative Information [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 September 30, 2018 (dollars in thousands):

	Fair Value (Net) at
	September 30, 2018			Valuation Technique	Unobservable Input	Range
Power exchange agreement	$	(5,909	)	Surrogate facility pricing	O&M charges	$40.05-$52.59/MWh (1)
					Transaction volumes	292,145 MWhs
Natural gas exchange agreement	$	(3,004	)	Internally derived weighted average cost of gas	Forward purchase prices	$1.40 - $1.83/mmBTU
					Forward sales prices	$1.46 - $3.21/mmBTU
					Purchase volumes	125,000 - 310,000 mmBTUs
					Sales volumes	60,000 - 310,000 mmBTUs

Carrying Value and Estimated Fair Value of Financial Instruments

The following table sets forth the carrying value and estimated fair value of the Company’s financial instruments not reported at estimated fair value on the Condensed Consolidated Balance Sheets as of September 30, 2018 and December 31, 2017 (dollars in thousands):

	September 30, 2018				December 31, 2017
	Carrying Value		Estimated Fair Value		Carrying Value		Estimated Fair Value
Long-term debt (Level 2)	$	1,053,500	$	1,116,014	$	951,000	$	1,067,783
Long-term debt (Level 3)	767,000		759,374		767,000		810,598
Snettisham capital lease obligation (Level 3)	57,844		56,200		59,745		61,700
Long-term debt to affiliated trusts (Level 3)	51,547		39,176		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
September 30, 2018
Assets:
Energy commodity derivatives	$	—	$	37,735	$	—	$	(36,851	)	$	884
Level 3 energy commodity derivatives:
Natural gas exchange agreement	—		—		22		(22		)	—
Foreign currency exchange derivatives	—		26		—		—			26
Interest rate swap derivatives	—		18,158		—		(129		)	18,029
Deferred compensation assets:
Mutual Funds:
Fixed income securities (2)	1,819		—		—		—			1,819
Equity securities (2)	6,712		—		—		—			6,712
Total	$	8,531	$	55,919	$	22	$	(37,002	)	$	27,470

	Level 1		Level 2		Level 3		Counterparty and Cash Collateral Netting (1)			Total
Liabilities:
Energy commodity derivatives	$	—	$	57,615	$	—	$	(56,200	)	$	1,415
Level 3 energy commodity derivatives:
Natural gas exchange agreement	—		—		3,026		(22		)	3,004
Power exchange agreement	—		—		5,909		—			5,909
Interest rate swap derivatives	—		4,577		—		(129		)	4,448
Total	$	—	$	62,192	$	8,935	$	(56,351	)	$	14,776
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
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 Condensed 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
Three months ended September 30, 2018:
Balance as of July 1, 2018	$	(3,480	)	$	(6,345	)	$	(9,825	)
Total gains or (losses) (realized/unrealized):
Included in regulatory assets/liabilities (1)	476			436			912
Settlements	—			—			—
Ending balance as of September 30, 2018 (2)	$	(3,004	)	$	(5,909	)	$	(8,913	)
Three months ended September 30, 2017:
Balance as of July 1, 2017	$	(4,173	)	$	(13,784	)	$	(17,957	)
Total gains or (losses) (realized/unrealized):
Included in regulatory assets/liabilities (1)	617			(2,870		)	(2,253		)
Settlements	(43		)	—			(43		)
Ending balance as of September 30, 2017 (2)	$	(3,599	)	$	(16,654	)	$	(20,253	)
Nine months ended September 30, 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)	(89		)	1,156			1,067
Settlements	249			6,180			6,429
Ending balance as of September 30, 2018 (2)	$	(3,004	)	$	(5,909	)	$	(8,913	)
Nine months ended September 30, 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)	2,434			(8,035		)	(5,601		)
Settlements	(148		)	4,830			4,682
Ending balance as of September 30, 2017 (2)	$	(3,599	)	$	(16,654	)	$	(20,253	)

(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.