Taxes (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Income Tax Disclosure [Line Items]
Effective income tax rate	36.10%	35.10%	36.40%	36.10%
MGE [Member]
Income Tax Disclosure [Line Items]
Effective income tax rate	36.00%	35.10%	36.40%	36.10%