Revenue:

9 Months Ended

Sep. 30, 2020

Revenue from Contract with Customer [Abstract]

Revenue

Revenue

Our revenue contracts generally provide for performance obligations that: are fulfilled and transfer control to customers over time; represent a series of distinct services that are substantially the same; involve the same pattern of transfer to the customer; and provide a right to consideration from our customers in an amount that corresponds directly with the value to the customer for the performance completed to date. Therefore, we recognize revenue in the amount to which we have a right to invoice. The following tables depict the disaggregation of revenue, including intercompany revenue, from contracts with customers by customer type and timing of revenue recognition for each of the reportable segments for the three and nine months ended September 30, 2020 and 2019. Sales tax and other similar taxes are excluded from revenues.

Three Months Ended September 30, 2020	Electric Utilities		Gas Utilities		Power Generation		Mining		Inter-company Revenues		Total
Customer types:	(in thousands)
Retail	$	169,505	$	94,367	$	—	$	14,668	$	(8,100)	$	270,440
Transportation	—		38,196		—		—		(139)		38,057
Wholesale	5,925		—		26,049		—		(24,521)		7,453
Market - off-system sales	9,535		36		—		—		(1,904)		7,667
Transmission/Other	15,653		10,277		—		—		(5,235)		20,695
Revenue from contracts with customers	$	200,618	$	142,876	$	26,049	$	14,668	$	(39,899)	$	344,312
Other revenues	224		1,053		469		568		(36)		2,278
Total revenues	$	200,842	$	143,929	$	26,518	$	15,236	$	(39,935)	$	346,590
Timing of revenue recognition:
Services transferred at a point in time	$	—	$	—	$	—	$	14,668	$	(8,100)	$	6,568
Services transferred over time	200,618		142,876		26,049		—		(31,799)		337,744
Revenue from contracts with customers	$	200,618	$	142,876	$	26,049	$	14,668	$	(39,899)	$	344,312

Three Months Ended September 30, 2019	Electric Utilities		Gas Utilities		Power Generation		Mining		Inter-company Revenues		Total
Customer Types:
Retail	$	162,214	$	89,810	$	—	$	14,992	$	(8,146)	$	258,870
Transportation	—		29,019		—		—		(195)		28,824
Wholesale	8,210		—		16,119		—		(14,414)		9,915
Market - off-system sales	6,452		139		—		—		(1,488)		5,103
Transmission/Other	14,274		10,965		—		—		(4,206)		21,033
Revenue from contracts with customers	$	191,150	$	129,933	$	16,119	$	14,992	$	(28,449)	$	323,745
Other revenues	234		811		9,692		560		(9,494)		1,803
Total Revenues	$	191,384	$	130,744	$	25,811	$	15,552	$	(37,943)	$	325,548
Timing of Revenue Recognition:
Services transferred at a point in time	$	—	$	—	$	—	$	14,992	$	(8,146)	$	6,846
Services transferred over time	191,150		129,933		16,119		—		(20,303)		316,899
Revenue from contracts with customers	$	191,150	$	129,933	$	16,119	$	14,992	$	(28,449)	$	323,745

Nine Months Ended September 30, 2020	Electric Utilities		Gas Utilities		Power Generation		Mining		Inter-company Revenues		Total
Customer types:	(in thousands)
Retail	$	459,949	$	513,208	$	—	$	43,917	$	(23,855)	$	993,219
Transportation	—		113,096		—		—		(416)		112,680
Wholesale	14,947		—		77,234		—		(72,609)		19,572
Market - off-system sales	17,940		197		—		—		(6,123)		12,014
Transmission/Other	43,271		32,038		—		—		(14,080)		61,229
Revenue from contracts with customers	$	536,107	$	658,539	$	77,234	$	43,917	$	(117,083)	$	1,198,714
Other revenues	2,074		7,273		1,372		1,940		(819)		11,840
Total revenues	$	538,181	$	665,812	$	78,606	$	45,857	$	(117,902)	$	1,210,554
Timing of revenue recognition:
Services transferred at a point in time	$	—	$	—	$	—	$	43,917	$	(23,855)	$	20,062
Services transferred over time	536,107		658,539		77,234		—		(93,228)		1,178,652
Revenue from contracts with customers	$	536,107	$	658,539	$	77,234	$	43,917	$	(117,083)	$	1,198,714

Nine Months Ended September 30, 2019	Electric Utilities		Gas Utilities		Power Generation		Mining		Inter-company Revenues		Total
Customer Types:
Retail	$	455,409	$	567,715	$	—	$	43,249	$	(23,315)	$	1,043,058
Transportation	—		102,159		—		—		(903)		101,256
Wholesale	23,334		—		46,650		—		(40,923)		29,061
Market - off-system sales	16,592		517		—		—		(5,047)		12,062
Transmission/Other	42,865		35,767		—		—		(12,608)		66,024
Revenue from contracts with customers	$	538,200	$	706,158	$	46,650	$	43,249	$	(82,796)	$	1,251,461
Other revenues	2,465		1,135		29,114		1,777		(28,706)		5,785
Total Revenues	$	540,665	$	707,293	$	75,764	$	45,026	$	(111,502)	$	1,257,246
Timing of Revenue Recognition:
Services transferred at a point in time	$	—	$	—	$	—	$	43,249	$	(23,315)	$	19,934
Services transferred over time	538,200		706,158		46,650		—		(59,481)		1,231,527
Revenue from contracts with customers	$	538,200	$	706,158	$	46,650	$	43,249	$	(82,796)	$	1,251,461

Contract Balances

The nature of our primary revenue contracts provides an unconditional right to consideration upon service delivery; therefore, no customer contract assets or liabilities exist. The unconditional right to consideration is represented by the balance in our Accounts Receivable further discussed in Note 4.