Commitments and Contingencies (Details-5) (USD $)	Dec. 31, 2013
MGE [Member]
Other Commitments [Line Items]
Other commitments, due in 2014	$ 1,473,000
Other commitments, due in 2015	474,000
Other commitments, due in 2016	475,000
Other commitments, due in 2017	433,000
Other commitments, due in 2018	435,000
Other commitment, due thereafter	6,961,000
MGE Energy [Member] | Investments in Non Public Entities, Capital Infusions [Member]
Other Commitments [Line Items]
Other commitment, initial agreed upon commitment total	1,700,000
MGE Energy [Member] | Venture Debt Fund [Member]
Other Commitments [Line Items]
Other commitment, initial agreed upon commitment total	1,000,000
Other commitments, total as of balance sheet date	$ 500,000