Consolidated Balance Sheets (Parentheticals) (USD $) In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Receivables, Net
Reserve for uncollectible accounts receivable	$ 3,662	$ 3,994
Reserve for uncollectible other accounts receivable	439	595
Common shareholders' equity
Common stock, par value	$ 1	$ 1
Common stock, shares authorized	50,000	50,000
Common stock, shares issued	23,114	23,114
MGE [Member]
Receivables, Net
Reserve for uncollectible accounts receivable	3,662	3,994
Reserve for uncollectible other accounts receivable	$ 439	$ 595
Common shareholders' equity
Common stock, par value	$ 1	$ 1
Common stock, shares authorized	50,000	50,000
Common stock, shares issued	17,348	17,348