Jointly owned facilities

12 Months Ended

Dec. 31, 2017

Regulated Operations [Abstract]

Jointly owned facilities

Jointly Owned Facilities

The consolidated financial statements include the Company's ownership interests in the assets, liabilities and expenses of the Big Stone Station, Coyote Station and Wygen III. Each owner of the stations is responsible for financing its investment in the jointly owned facilities.

The Company's share of the stations operating expenses was reflected in the appropriate categories of operating expenses (fuel, operation and maintenance and taxes, other than income) in the Consolidated Statements of Income.

At December 31, the Company's share of the cost of utility plant in service and related accumulated depreciation for the stations was as follows:

	2017		2016
	(In thousands)
Big Stone Station:
Utility plant in service	$	158,084	$	157,144
Less accumulated depreciation	51,740		49,568
	$	106,344	$	107,576
Coyote Station:
Utility plant in service	$	155,287	$	156,334
Less accumulated depreciation	103,897		105,928
	$	51,390	$	50,406
Wygen III:
Utility plant in service	$	65,065	$	66,251
Less accumulated depreciation	7,652		7,550
	$	57,413	$	58,701