Revenue from contracts with customers (Tables)

12 Months Ended

Dec. 31, 2018

Revenue from Contract with Customer [Abstract]

Disaggregation of revenue

In the following table, revenue is disaggregated by the type of customer or service provided. The Company believes this level of disaggregation best depicts how the nature, amount, timing and uncertainty of revenue and cash flows are affected by economic factors. The table also includes a reconciliation of the disaggregated revenue by reportable segments. For more information on the Company's business segments, see Note 15.

Year ended December 31, 2018	Electric		Natural gas distribution		Pipeline and midstream			Construction materials and contracting			Construction services			Other			Total
	(In thousands)
Residential utility sales	$	121,477	$	457,959	$	—		$	—		$	—		$	—		$	579,436
Commercial utility sales	136,236		276,716		—			—			—			—			412,952
Industrial utility sales	34,353		24,603		—			—			—			—			58,956
Other utility sales	7,556		—		—			—			—			—			7,556
Natural gas transportation	—		43,238		89,159			—			—			—			132,397
Natural gas gathering	—		—		9,159			—			—			—			9,159
Natural gas storage	—		—		11,543			—			—			—			11,543
Contracting services	—		—		—			968,755			—			—			968,755
Construction materials	—		—		—			1,423,068			—			—			1,423,068
Intrasegment eliminations*	—		—		—			(465,969		)	—			—			(465,969		)
Inside specialty contracting	—		—		—			—			926,875			—			926,875
Outside specialty contracting	—		—		—			—			392,544			—			392,544
Other	31,568		14,579		18,865			—			525			11,259			76,796
Intersegment eliminations	—		—		(50,905		)	(669		)	(1,681		)	(11,052		)	(64,307		)
Revenues from contracts with customers	331,190		817,095		77,821			1,925,185			1,318,263			207			4,469,761
Revenues out of scope	3,933		6,152		197			—			51,509			—			61,791
Total external operating revenues	$	335,123	$	823,247	$	78,018		$	1,925,185		$	1,369,772		$	207		$	4,531,552

* Intrasegment revenues are presented within the construction materials and contracting segment to highlight the focus on vertical integration as this segment sells materials to both third parties and internal customers. Due to consolidation requirements, these revenues must be eliminated against construction materials to arrive at the external operating revenue total for the segment.

Contract balances

The changes in contract assets and liabilities were as follows:

	December 31, 2018			December 31, 2017			Change			Location on Consolidated Balance Sheets
	(In thousands)
Contract assets	$	104,239		$	109,540		$	(5,301	)	Receivables, net
Contract liabilities - current	(93,901		)	(84,123		)	(9,778		)	Accounts payable
Contract liabilities - noncurrent	(135		)	—			(135		)	Deferred credits and other liabilities - other
Net contract assets	$	10,203		$	25,417		$	(15,214	)