Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2016

Financial Assets And Liabilities Measured At Fair Value On A Recurring Basis

The following table summarizes our financial assets and liabilities measured at fair value on a recurring basis as of December 31, 2016 and 2015:

			Quoted Prices
			in Active		Significant
			Markets for		Other		Significant
			Identical		Observable		Observable
	December 31,		Assets		Inputs		Inputs
	2016		(Level 1)		(Level 2)		(Level 3)
	(in thousands)
Nuclear decommissioning trust ⁽¹⁾	$	48,142	$	48,142	$	—	$	—
Nuclear decommissioning trust - net asset value ⁽¹⁾⁽²⁾		111,013		—		—		—
Unrestricted investments and other ⁽³⁾		247		—		247		—
Derivatives - gas and power ⁽⁴⁾		6,968		4,874		2,094		—
Total Financial Assets	$	166,370	$	53,016	$	2,341	$	—

			Quoted Prices
			in Active		Significant
			Markets for		Other		Significant
			Identical		Observable		Observable
	December 31,		Assets		Inputs		Inputs
	2015		(Level 1)		(Level 2)		(Level 3)
	(in thousands)
Nuclear decommissioning trust ⁽¹⁾	$	46,051	$	46,051	$	—	$	—
Nuclear decommissioning trust - net asset value ⁽¹⁾⁽²⁾		99,664		—		—		—
Unrestricted investments and other ⁽³⁾		211		—		211		—
Total Financial Assets	$	145,926	$	46,051	$	211	$	—

Derivatives - gas and power ⁽⁴⁾	$	3,653	$	3,653	$	—	$	—
Total Financial Liabilities	$	3,653	$	3,653	$	—	$	—

⁽¹⁾

For additional information about our nuclear decommissioning trust, see Note 9—Investments.

⁽²⁾

Nuclear decommissioning trust includes investments measured at net asset value per share (or its equivalent) as a practical expedient and these investments have not been categorized in the fair value hierarchy. The fair value amounts presented in this table are intended to permit reconciliation of the fair value hierarchy to the amounts presented in the Consolidated Balance Sheet.

⁽³⁾

Unrestricted investments and other includes investments that are related to equity securities.

⁽⁴⁾

Derivatives – gas and power represent natural gas futures contracts. Level 1 are indexed against NYMEX. Level 2 are valued by ACES using observable market inputs for similar transactions. For additional information about our derivative financial instruments, see Note 1—Summary of Significant Accounting Policies.