Revenue Recognition

We recognize revenue when our performance obligations under contracts with customers have been satisfied, which generally occurs when our businesses have delivered or transported natural gas, electricity or propane to customers. We exclude sales taxes and other similar taxes from the transaction price. Typically, our customers pay for the goods and/or services we provide in the month following the satisfaction of our performance obligation.

The following table displays our revenue by major source based on product and service type for the three months ended March 31, 2019 and 2018:



	Three months ended March 31, 2019												Three Months Ended March 31, 2018
(in thousands)	Regulated Energy			Unregulated Energy			Other and Eliminations			Total			Regulated Energy			Unregulated Energy			Other and Eliminations			Total
Energy distribution
Delaware natural gas division	$	27,549		$	—		$	—		$	27,549		$	32,072		$	—		$	—		$	32,072
Florida natural gas division	7,900			—			—			7,900			5,864			—			—			5,864
FPU electric distribution	14,378			—			—			14,378			18,741			—			—			18,741
FPU natural gas distribution	23,786			—			—			23,786			23,213			—			—			23,213
Maryland natural gas division	10,047			—			—			10,047			10,672			—			—			10,672
Sandpiper natural gas/propane operations	7,082			—			—			7,082			8,964			—			—			8,964
Total energy distribution	90,742			—			—			90,742			99,526			—			—			99,526

Energy transmission
Aspire Energy	—			13,470			—			13,470			—			12,077			—			12,077
Eastern Shore	19,056			—			—			19,056			15,597			—			—			15,597
Peninsula Pipeline	3,565			—			—			3,565			2,098			—			—			2,098
Total energy transmission	22,621			13,470			—			36,091			17,695			12,077			—			29,772

Energy generation
Eight Flags	—			4,142			—			4,142			—			4,378			—			4,378

Propane operations
Propane delivery operations	—			46,125			—			46,125			—			52,104			—			52,104

Energy services
Marlin Gas Services	—			2,434			—			2,434			—			—			—			—
PESCO - Natural Gas Marketing	—			77,022			—			77,022						81,559			—			81,559
Total energy services	—			79,456			—			79,456			—			81,559			—			81,559

Other and eliminations
Eliminations	(9,745		)	(5,496		)	(14,236		)	(29,477		)	(7,828		)	(5,245		)	(15,598		)	(28,671		)
Other	—			405			132			537			—			494			194			688
Total other and eliminations	(9,745		)	(5,091		)	(14,104		)	(28,940		)	(7,828		)	(4,751		)	(15,404		)	(27,983		)

Total operating revenues⁽¹⁾	$	103,618		$	138,102		$	(14,104	)	$	227,616		$	109,393		$	145,367		$	(15,404	)	$	239,356

⁽¹⁾ Total operating revenues for the three months ended March 31, 2019, include other revenue (revenues from sources other than contracts with customers) of $121,000 and $84,000 for our Regulated and Unregulated Energy segments, respectively and $(589,000) and $73,000 for our Regulated and Unregulated Energy segments, respectively, for the three months ended March 31, 2018. The sources of other revenues include revenue from alternative revenue programs related to revenue normalization for the Maryland division and Sandpiper and late fees.

Contract balances

The timing of revenue recognition, customer billings and cash collections results in trade receivables, unbilled receivables (contract assets), and customer advances (contract liabilities) in our condensed consolidated balance sheets. The balances of our trade receivables, contract assets, and contract liabilities as of December 31, 2018 and March 31, 2019 were as follows:



	Trade Receivables			Contract Assets (Non-current)		Contract Liabilities (Current)
(in thousands)
Balance at 12/31/2018	$	83,214		$	2,614	$	480
Balance at 3/31/2019	72,162			3,004		305
Increase (decrease)	$	(11,052	)	$	390	$	(175	)

Our trade receivables are included in trade and other receivables in the condensed consolidated balance sheets. Our non-current contract assets are included in other assets in the condensed consolidated balance sheet and relate to operations and maintenance costs incurred by Eight Flags that have not yet been recovered through rates for the sale of electricity to our electric distribution operation pursuant to a long-term service agreement.

At times, we receive advances or deposits from our customers before we satisfy our performance obligation, resulting in contract liabilities. At March 31, 2019 and December 31, 2018, we had a contract liability of $305,000 and $480,000, respectively, which was included in other accrued liabilities in the condensed consolidated balance sheet, and which relates to non-refundable prepaid fixed fees for our Delmarva Peninsula propane delivery operation's retail offerings. Our performance obligation is satisfied over the term of the respective retail offering plan on a ratable basis. For the three months ended March 31, 2019 and 2018, we recognized revenue of $287,000 and $251,000, respectively.

Remaining performance obligations

Our businesses have long-term fixed fee contracts with customers in which revenues are recognized as performance obligations are satisfied over the contract term. Revenue for these businesses for the remaining performance obligations at March 31, 2019 are expected to be recognized as follows:



(in thousands)	2019		2020		2021		2022		2023		2024		2025 and thereafter
Eastern Shore and Peninsula Pipeline	$	28,754	$	36,791	$	33,510	$	26,566	$	21,146	$	18,969	$	193,651
Natural gas distribution operations	2,999		3,587		3,358		3,320		2,924		2,910		27,916
PESCO - Natural Gas Marketing	4,435		4,585		1,706		22		—		—		—
FPU electric distribution	223		297		297		109		—		—		—
Total revenue contracts with remaining performance obligations	$	36,411	$	45,260	$	38,871	$	30,017	$	24,070	$	21,879	$	221,567