Fair Value of Financial Instruments (Tables)

6 Months Ended

Jun. 30, 2017

Fair Value Disclosures [Abstract]

Financial Assets and Liabilities Measured at Fair Value on Recurring Basis

The following table summarizes our financial assets and liabilities that are measured at fair value on a recurring basis and the fair value measurements, by level, within the fair value hierarchy as of June 30, 2017 and December 31, 2016:

			Fair Value Measurements Using:
As of June 30, 2017	Fair Value		Quoted- Prices- in Active Markets (Level 1)		Significant- Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
(in thousands)
Assets:
Investments—equity securities	$	22	$	22	$	—	$	—
Investments—guaranteed income fund	630		—		—		630
Investments—mutual funds and other	5,300		5,300		—		—
Total investments	5,952		5,322		—		630
Mark-to-market energy assets, incl. natural gas futures contracts and swap agreements	229		—		229		—
Total assets	$	6,181	$	5,322	$	229	$	630
Liabilities:
Mark-to-market energy liabilities including natural gas futures contracts	$	188	$	—	$	188	$	—

			Fair Value Measurements Using:
As of December 31, 2016	Fair Value		Quoted- Prices- in Active Markets (Level 1)		Significant- Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
(in thousands)
Assets:
Investments—equity securities	$	21	$	21	$	—	$	—
Investments—guaranteed income fund	561		—		—		561
Investments—mutual funds and other	4,320		4,320		—		—
Total investments	4,902		4,341		—		561
Mark-to-market energy assets, incl. natural gas futures contracts and swap agreements	823		—		823		—
Total assets	$	5,725	$	4,341	$	823	$	561
Liabilities:
Mark-to-market energy liabilities including natural gas futures contracts	$	773	$	—	$	773	$	—

Summary of Changes in Fair Value of Investments

The following table sets forth the summary of the changes in the fair value of Level 3 investments for the six months ended June 30, 2017 and 2016:

	Six Months Ended   June 30,
	2017		2016
(in thousands)
Beginning Balance	$	561	$	279
Purchases and adjustments	65		112
Transfers	—		88
Distribution	—		(8		)
Investment income	4		4
Ending Balance	$	630	$	475