Property, Plant, and Equipment (Tables)

12 Months Ended

Dec. 31, 2017

Property, Plant and Equipment [Abstract]

Schedule of Property, Plant, and Equipment

Property, plant, and equipment consisted of the following at December 31:

		MGE Energy				MGE
(In thousands)		2017		2016		2017		2016
Utility:
Electric(a)	$	1,209,336	$	1,171,004	$	1,209,353	$	1,171,021
Gas		415,542		395,790		415,553		395,801
Total utility plant		1,624,878		1,566,794		1,624,906		1,566,822
Less: Accumulated depreciation and amortization(a)		599,469		579,965		599,469		579,965
In-service utility plant, net		1,025,409		986,829		1,025,437		986,857
Nonregulated:
Nonregulated		319,611		317,810		319,611		317,014
Less: Accumulated depreciation and amortization		61,707		59,370		61,707		59,223
In-service nonregulated plant, net		257,904		258,440		257,904		257,791
Construction work in progress:
Utility construction work in progress(a)		56,208		31,356		56,208		31,356
Nonregulated construction work in progress		1,836		5,434		1,836		5,434
Total property, plant, and equipment	$	1,341,357	$	1,282,059	$	1,341,385	$	1,281,438

(a)As of December 31,2017 and 2016, MGE has classified $8.8 million and $14.8 million, respectively,of Columbia assets as held-for-sale on the consolidated balance sheets related to the partial sale of plant assets to WPL. See Footnote 5.a. for further discussion.