Fair Value of Financial Instruments (Tables)

3 Months Ended

Mar. 31, 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 March 31, 2017 and December 31, 2016:

			Fair Value Measurements Using:
As of March 31, 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	565		—		—		565
Investments—mutual funds and other	4,625		4,625		—		—
Total investments	5,212		4,647		—		565
Mark-to-market energy assets, incl. natural gas futures contracts and swap agreements	1,339		—		1,339		—
Total assets	$	6,551	$	4,647	$	1,339	$	565
Liabilities:
Mark-to-market energy liabilities including natural gas futures contracts	$	189	$	—	$	189	$	—

			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 three months ended March 31, 2017 and 2016:

	Three Months Ended   March 31,
	2017		2016
(in thousands)
Beginning Balance	$	561	$	279
Purchases and adjustments	2		2
Transfers	—		242
Investment income	2		2
Ending Balance	$	565	$	525