Fair Value (Tables)

9 Months Ended

Sep. 30, 2017

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, 2017 (dollars in thousands):

	Fair Value (Net) at
	September 30, 2017			Valuation Technique	Unobservable Input	Range
Power exchange agreement	$	(16,654	)	Surrogate facility pricing	O&M charges	$38.87-$45.20/MWh (1)
					Escalation factor	5% - 2018 to 2019
					Transaction volumes	396,984 - 432,357 MWhs
Power option agreement	$	(12	)	Black-Scholes- Merton	Strike price	$34.85/MWh - 2019
						$47.54/MWh - 2018
					Delivery volumes	157,517 - 222,683 MWhs
Natural gas exchange agreement	$	(3,599	)	Internally derived weighted average cost of gas	Forward purchase prices	$1.70 - $2.24/mmBTU
					Forward sales prices	$1.63 - $3.20/mmBTU
					Purchase volumes	115,000 - 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, 2017 and December 31, 2016 (dollars in thousands):

	September 30, 2017				December 31, 2016
	Carrying Value		Estimated Fair Value		Carrying Value		Estimated Fair Value
Long-term debt (Level 2)	$	951,000	$	1,072,557	$	951,000	$	1,048,661
Long-term debt (Level 3)	677,000		704,130		677,000		675,251
Snettisham capital lease obligation (Level 3)	60,349		62,000		62,160		62,800
Long-term debt to affiliated trusts (Level 3)	51,547		41,238		51,547		38,660

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, 2017
Assets:
Energy commodity derivatives	$	—	$	37,902	$	—	$	(37,775	)	$	127
Level 3 energy commodity derivatives:
Natural gas exchange agreement	—		—		90		(90		)	—
Interest rate swap derivatives	—		7,983		—		(2,145		)	5,838
Deferred compensation assets:
Fixed income securities (2)	1,692		—		—		—			1,692
Equity securities (2)	6,276		—		—		—			6,276
Total	$	7,968	$	45,885	$	90	$	(40,010	)	$	13,933
Liabilities:
Energy commodity derivatives	$	—	$	56,013	$	—	$	(53,422	)	$	2,591
Level 3 energy commodity derivatives:
Natural gas exchange agreement	—		—		3,689		(90		)	3,599
Power exchange agreement	—		—		16,654		—			16,654
Power option agreement	—		—		12		—			12
Foreign currency exchange derivatives	—		51		—		—			51
Interest rate swap derivatives	—		72,355		—		(36,505		)	35,850
Total	$	—	$	128,419	$	20,355	$	(90,017	)	$	58,757

	Level 1		Level 2		Level 3		Counterparty and Cash Collateral Netting (1)			Total
December 31, 2016
Assets:
Energy commodity derivatives	$	—	$	47,994	$	—	$	(46,099	)	$	1,895
Level 3 energy commodity derivatives:
Natural gas exchange agreement	—		—		69		(69		)	—
Power exchange agreement	—		—		25		(25		)	—
Foreign currency exchange derivatives	—		5		—		(5		)	—
Interest rate swap derivatives	—		13,098		—		(4,348		)	8,750
Deferred compensation assets:
Fixed income securities (2)	1,789		—		—		—			1,789
Equity securities (2)	5,481		—		—		—			5,481
Total	$	7,270	$	61,097	$	94	$	(50,546	)	$	17,915
Liabilities:
Energy commodity derivatives	$	—	$	56,871	$	—	$	(55,957	)	$	914
Level 3 energy commodity derivatives:
Natural gas exchange agreement	—		—		5,954		(69		)	5,885
Power exchange agreement	—		—		13,474		(25		)	13,449
Power option agreement	—		—		76		—			76
Foreign currency exchange derivatives	—		28		—		(5		)	23
Interest rate swap derivatives	—		73,978		—		(39,248		)	34,730
Total	$	—	$	130,877	$	19,504	$	(95,304	)	$	55,077

(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 trading securities and 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			Power Option Agreement			Total
Three months ended September 30, 2017:
Balance as of July 1, 2017	$	(4,173	)	$	(13,784	)	$	(43	)	$	(18,000	)
Total gains or (losses) (realized/unrealized):
Included in regulatory assets/liabilities (1)	617			(2,870		)	31			(2,222		)
Settlements	(43		)	—			—			(43		)
Ending balance as of September 30, 2017 (2)	$	(3,599	)	$	(16,654	)	$	(12	)	$	(20,265	)
Three months ended September 30, 2016:
Balance as of July 1, 2016	$	(6,857	)	$	(14,614	)	$	(105	)	$	(21,576	)
Total gains or (losses) (realized/unrealized):
Included in regulatory assets/liabilities (1)	336			(1,696		)	(692		)	(2,052		)
Settlements	—			—			—			—
Ending balance as of September 30, 2016 (2)	$	(6,521	)	$	(16,310	)	$	(797	)	$	(23,628	)
Nine months ended September 30, 2017:
Balance as of January 1, 2017	$	(5,885	)	$	(13,449	)	$	(76	)	$	(19,410	)
Total gains or (losses) (realized/unrealized):
Included in regulatory assets/liabilities (1)	2,434			(8,035		)	64			(5,537		)
Settlements	(148		)	4,830			—			4,682
Ending balance as of September 30, 2017 (2)	$	(3,599	)	$	(16,654	)	$	(12	)	$	(20,265	)
Nine months ended September 30, 2016:
Balance as of January 1, 2016	$	(5,039	)	$	(21,961	)	$	(124	)	$	(27,124	)
Total gains or (losses) (realized/unrealized):
Included in regulatory assets/liabilities (1)	(2,960		)	272			(673		)	(3,361		)
Settlements	1,478			5,379			—			6,857
Ending balance as of September 30, 2016 (2)	$	(6,521	)	$	(16,310	)	$	(797	)	$	(23,628	)

(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.