Commitments and Contingencies (Details-2) (USD $)	9 Months Ended
	Sep. 30, 2013
Chattel Paper Purchase Agreement [Abstract]
Chattel paper purchase agreement maximum interest	$ 10,000,000
Outstanding interest in chattel paper receivables	5,000,000
Servicing asset recognized	300,000
Operating expense purchase contracts [Abstract]
Purchase obligation due in remainder of fiscal year	73,044,000
Purchase obligation due in second year	80,568,000
Purchase obligation due in third year	57,697,000
Purchase obligation due in fourth year	52,565,000
Purchase obligation due in fifth year	50,856,000
Chattel Paper [Member]
Contractual obligation [Abstract]
Contractual obligation due in remainder of fiscal year	213,000
Contractual obligation due in second year	621,000
Contractual obligation due in third year	937,000
Contractual obligation due in fourth year	862,000
Contractual obligation due in fifth year	455,000
Coal Commitment [Member]
Operating expense purchase contracts [Abstract]
Purchase obligation due in remainder of fiscal year	7,407,000	[1]
Purchase obligation due in second year	17,705,000	[1]
Purchase obligation due in third year	9,921,000	[1]
Purchase obligation due in fourth year	3,770,000	[1]
Purchase obligation due in fifth year	1,040,000	[1]
Natural Gas Supply Commitment [Member]
Operating expense purchase contracts [Abstract]
Purchase obligation due in remainder of fiscal year	14,549,000	[2]
Purchase obligation due in second year	13,601,000	[2]
Purchase obligation due in third year	0	[2]
Purchase obligation due in fourth year	0	[2]
Purchase obligation due in fifth year	0	[2]
Purchase Power Commitment [Member]
Operating expense purchase contracts [Abstract]
Purchase obligation due in remainder of fiscal year	49,397,000	[3]
Purchase obligation due in second year	49,262,000	[3]
Purchase obligation due in third year	47,776,000	[3]
Purchase obligation due in fourth year	48,795,000	[3]
Purchase obligation due in fifth year	49,816,000	[3]
Other Commitment [Member]
Operating expense purchase contracts [Abstract]
Purchase obligation due in remainder of fiscal year	1,691,000
Purchase obligation due in second year	0
Purchase obligation due in third year	0
Purchase obligation due in fourth year	0
Purchase obligation due in fifth year	$ 0
Chattel Paper [Member] | Minimum [Member]
Chattel Paper Purchase Agreement [Abstract]
Guarantee to financial institution, term	1 year
Chattel Paper [Member] | Maximum [Member]
Chattel Paper Purchase Agreement [Abstract]
Guarantee to financial institution, term	10 years

[1] Total coal commitments for the Columbia and Elm Road Units, including transportation. Fuel procurement for MGE’s jointly owned Columbia and Elm Road Units are handled by WPL and WEPCO, respectively, who are the operators of those facilities. If any minimum purchase obligations must be paid under these contracts, management believes these obligations would be considered costs of service and recoverable in rates.

[2] These commitments include market-based pricing. Management expects to recover these costs in future customer rates.

[3] MGE has several purchase power agreements to help meet future electric supply requirements. Management expects to recover these costs in future customer rates.