Investments (Details-1) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Available-for-sale securities [Abstract]
Cost basis	$ 1,347,000	$ 1,316,000
Gross unrealized gains	196,000	243,000
Gross unrealized losses	(9,000)	(6,000)
Fair Value	1,534,000	1,553,000
Equity method investments [Abstract]
Equity method investments	56,996,000	54,292,000
Other Investments	1,802,000	0
Total investments	60,332,000	55,845,000
Sale of investments [Abstract]
Proceeds from sale of investments	300,000	200,000	100,000
Gain on sale of investments	200,000	100,000	100,000
ATC [Member]
Equity method investments [Abstract]
Equity method investments	56,975,000	54,200,000
Other Equity Method Investments [Member]
Equity method investments [Abstract]
Equity method investments	21,000	92,000
MGE [Member]
Available-for-sale securities [Abstract]
Cost basis	482,000	536,000
Gross unrealized gains	87,000	125,000
Gross unrealized losses	(9,000)	(6,000)
Fair Value	560,000	655,000
Equity method investments [Abstract]
Equity method investments	56,996,000	54,292,000
Other Investments	0	0
Total investments	57,556,000	54,947,000
Sale of investments [Abstract]
Proceeds from sale of investments	200,000	100,000
Gain on sale of investments	200,000	100,000
MGE [Member] | ATC [Member]
Equity method investments [Abstract]
Equity method investments	56,975,000	54,200,000
MGE [Member] | Other Equity Method Investments [Member]
Equity method investments [Abstract]
Equity method investments	$ 21,000	$ 92,000