Schedule I - Condensed Parent Company Finanical Statements (Details-Balance Sheet) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014		Dec. 31, 2013	Dec. 31, 2012
Current Assets:
Cash and cash equivalents	$ 81,384	$ 65,755		$ 68,813	$ 46,357
Accounts receivable, net:
Other current assets	10,570	10,711
Total Current Assets	254,751	250,477
Other deferred assets and other	5,602	4,837
Investments:
Other investments	159	159
Total investments	73,631	71,760
Total Assets	1,730,673	1,694,184	[1]	1,579,060
Current Liabilities:
Other current liabilities	4,910	13,931
Total Current Liabilities	84,146	89,996
Other Credits:
Deferred income taxes	360,785	338,563	[1]
Total Other Credits	565,055	549,531	[1]
Shareholders' Equity:
Retained income	339,165	308,007
Other comprehensive income (loss)	357	458
Total Common Shareholders' Equity	690,458	659,401		617,510	579,429
Commitments and contingencies (see Footnote 3)	0	0
Total Liabilities and Capitalization	1,730,673	1,694,184	[1]
MGE Energy [Member]
Current Assets:
Cash and cash equivalents	51,781	58,429		$ 51,204	$ 36,881
Accounts receivable, net:
Accounts receivable from affiliates	20	64
Other current assets	1,386	2,809
Total Current Assets	53,187	61,302
Other deferred assets and other	249	140
Investments:
Investments in affiliates	649,276	619,563
Other investments	1,447	1,177
Total investments	650,723	620,740
Total Assets	704,159	682,182	[1]
Current Liabilities:
Accounts payable to affiliates	530	7,096
Accrued taxes	263	663
Other current liabilities	144	2,601
Total Current Liabilities	937	10,360
Other Credits:
Deferred income taxes	7,998	7,125	[1]
Accounts payable to affiliates	4,766	5,296
Total Other Credits	12,764	12,421	[1]
Shareholders' Equity:
Common shareholders' equity	350,936	350,936
Retained income	339,165	308,007
Other comprehensive income (loss)	357	458
Total Common Shareholders' Equity	690,458	659,401
Commitments and contingencies (see Footnote 3)	0	0
Total Liabilities and Capitalization	$ 704,159	$ 682,182	[1]

[1] Reflects retrospective application of new accounting pronouncement. See Footnote 12 for additional information.