Business segment data

12 Months Ended

Dec. 31, 2020

Segment Reporting [Abstract]

Business segment data

Business Segment Data

The Company's reportable segments are those that are based on the Company's method of internal reporting, which generally segregates the strategic business units due to differences in products, services and regulation. The internal reporting of these operating segments is defined based on the reporting and review process used by the Company's chief executive officer. The Company's operations are located within the United States.

The electric segment generates, transmits and distributes electricity in Montana, North Dakota, South Dakota and Wyoming. The natural gas distribution segment distributes natural gas in those states, as well as in Idaho, Minnesota, Oregon and Washington. These operations also supply related value-added services.

The pipeline segment provides natural gas transportation and underground storage services through a regulated pipeline system primarily in the Rocky Mountain and northern Great Plains regions of the United States. This segment also provides non-regulated cathodic protection and other energy-related services. In 2020, the pipeline segment divested its regulated and non-regulated natural gas gathering assets. With the completion of these sales, the segment has exited the natural gas gathering business.

The construction materials and contracting segment mines, processes and sells construction aggregates (crushed stone, sand and gravel); produces and sells asphalt mix; and supplies ready-mixed concrete. This segment focuses on vertical integration of its contracting services with its construction materials to support the aggregate-based product lines including aggregate placement, asphalt and concrete paving, and site development and grading. Although not common to all locations, other products include the sale of cement, liquid asphalt for various commercial and roadway applications, various finished concrete products and other building materials and related contracting services. This segment operates in the central, southern and western United States, including Alaska and Hawaii.

The construction services segment provides inside and outside specialty contracting services in 44 states plus Washington D.C. Its inside services include design, construction and maintenance of electrical and communication wiring and infrastructure, fire suppression systems, and mechanical piping and services. Its outside services include design, construction and maintenance of overhead and underground electrical distribution and transmission lines, substations, external lighting, traffic signalization, and gas pipelines, as well as utility excavation and the manufacture and distribution of transmission line construction equipment. This segment also constructs and maintains renewable energy projects. These specialty contracting services are provided to utilities and large manufacturing, commercial, industrial, institutional and governmental customers.

The Other category includes the activities of Centennial Capital, which, through its subsidiary InterSource Insurance Company, insures various types of risks as a captive insurer for certain of the Company's subsidiaries. The function of the captive insurer is to fund the self-insured layers of the insured Company's general liability, automobile liability, pollution liability and other coverages. Centennial Capital also owns certain real and personal property. In addition, the Other category includes certain assets, liabilities and tax adjustments of the holding company primarily associated with corporate functions and certain general and administrative costs (reflected in operation and maintenance expense) and interest expense, which were previously allocated to the refining business and Fidelity and do not meet the criteria for income (loss) from discontinued operations. The Other category also includes Centennial Resources' former investment in Brazil.

Discontinued operations include the results and supporting activities of Dakota Prairie Refining and Fidelity other than certain general and administrative costs and interest expense as described above.

The information below follows the same accounting policies as described in Note 2. Information on the Company's segments as of December 31 and for the years then ended was as follows:

	2020		2019		2018
			(In thousands)
External operating revenues:
Regulated operations:
Electric	$	331,538	$	351,725	$	335,123
Natural gas distribution	847,651		865,222		823,247
Pipeline	69,957		62,357		54,857
	1,249,146		1,279,304		1,213,227
Non-regulated operations:
Pipeline	15,389		21,835		23,161
Construction materials and contracting	2,177,585		2,189,651		1,925,185
Construction services	2,090,685		1,845,896		1,369,772
Other	(55)		90		207
	4,283,604		4,057,472		3,318,325
Total external operating revenues	$	5,532,750	$	5,336,776	$	4,531,552

	2020		2019		2018
			(In thousands)
Intersegment operating revenues:
Regulated operations:
Electric	$	491	$	—	$	—
Natural gas distribution	534		—		—
Pipeline	57,977		56,037		50,580
	59,002		56,037		50,580
Non-regulated operations:
Pipeline	554		215		325
Construction materials and contracting	417		1,066		669
Construction services	5,038		3,370		1,681
Other	11,958		16,461		11,052
	17,967		21,112		13,727
Intersegment eliminations	(76,969)		(77,149)		(64,307)
Total intersegment operating revenues	$	—	$	—	$	—
Depreciation, depletion and amortization:
Electric	$	62,998	$	58,721	$	50,982
Natural gas distribution	84,580		79,564		72,486
Pipeline	21,669		21,220		17,896
Construction materials and contracting	89,626		77,450		61,158
Construction services	23,523		17,038		15,728
Other	2,704		2,024		1,955
Total depreciation, depletion and amortization	$	285,100	$	256,017	$	220,205
Operating income (loss):
Electric	$	63,434	$	64,039	$	65,148
Natural gas distribution	73,082		69,188		72,336
Pipeline	49,436		42,796		36,128
Construction materials and contracting	214,498		179,955		141,426
Construction services	147,644		126,426		86,764
Other	(3,169)		(1,184)		(79)
Total operating income	$	544,925	$	481,220	$	401,723
Interest expense:
Electric	$	26,699	$	25,334	$	25,860
Natural gas distribution	36,798		35,488		30,768
Pipeline	7,622		7,198		5,964
Construction materials and contracting	20,577		23,792		17,290
Construction services	4,095		5,331		3,551
Other	883		1,859		2,762
Intersegment eliminations	(155)		(415)		(1,581)
Total interest expense	$	96,519	$	98,587	$	84,614
Income tax expense (benefit):
Electric	$	(11,636)	$	(12,650)	$	(6,482)
Natural gas distribution	5,746		1,405		4,075
Pipeline	7,650		7,219		2,677
Construction materials and contracting	47,431		37,389		28,357
Construction services	35,797		29,973		20,000
Other	(398)		(57)		(1,142)
Total income expense	$	84,590	$	63,279	$	47,485

	2020		2019		2018
			(In thousands)
Net income (loss):
Regulated operations:
Electric	$	55,601	$	54,763	$	47,000
Natural gas distribution	44,049		39,517		37,732
Pipeline	35,453		28,255		26,905
	135,103		122,535		111,637
Non-regulated operations:
Pipeline	1,559		1,348		1,554
Construction materials and contracting	147,325		120,371		92,647
Construction services	109,721		92,998		64,309
Other	(3,181)		(2,086)		(761)
	255,424		212,631		157,749
Income from continuing operations	390,527		335,166		269,386
Income (loss) from discontinued operations, net of tax	(322)		287		2,932
Net income	$	390,205	$	335,453	$	272,318
Capital expenditures:
Electric	$	114,676	$	99,449	$	186,105
Natural gas distribution	193,048		206,799		205,896
Pipeline	62,224		71,477		70,057
Construction materials and contracting	191,635		190,092		280,396
Construction services	83,651		60,500		25,081
Other	3,045		8,181		1,768
Total capital expenditures (a)	$	648,279	$	636,498	$	769,303
Assets:
Electric (b)	$	2,123,693	$	1,680,194	$	1,613,822
Natural gas distribution (b)	2,302,770		2,574,965		2,375,871
Pipeline	703,377		677,482		616,959
Construction materials and contracting	1,798,493		1,684,161		1,508,032
Construction services	818,662		761,127		604,798
Other (c)	305,157		303,279		266,111
Assets held for sale	1,220		1,851		2,517
Total assets	$	8,053,372	$	7,683,059	$	6,988,110
Property, plant and equipment:
Electric (b)	$	2,323,403	$	2,227,145	$	2,148,569
Natural gas distribution (b)	2,868,853		2,688,123		2,499,093
Pipeline	821,697		834,215		764,959
Construction materials and contracting	2,028,476		1,910,562		1,768,006
Construction services	220,796		213,370		188,586
Other	37,545		35,213		28,108
Less accumulated depreciation, depletion and amortization	3,133,831		2,991,486		2,818,644
Net property, plant and equipment	$	5,166,939	$	4,917,142	$	4,578,677

(a)    Capital expenditures for 2020, 2019 and 2018 include noncash transactions such as the issuance of the Company's equity securities in connection with acquisitions, capital expenditure-related accounts payable, AFUDC and accrual of holdback payments in connection with acquisitions totaling $(15.7) million, $4.8 million and $33.4 million, respectively.

(b)    Includes allocations of common utility property.

(c)    Includes assets not directly assignable to a business (i.e. cash and cash equivalents, certain accounts receivable, certain investments and other miscellaneous current and deferred assets).