XML 88 R66.htm IDEA: XBRL DOCUMENT
v3.3.1.900

Common Equity (Details) $ / shares in Units, $ in Thousands |  | 3 Months Ended | 12 Months Ended
--- | --- | --- | ---
Dec. 20, 2013 | Dec. 31, 2015 $ / shares | Sep. 30, 2015 $ / shares | Jun. 30, 2015 $ / shares | Mar. 31, 2015 $ / shares | Dec. 31, 2014 $ / shares | Sep. 30, 2014 $ / shares | Jun. 30, 2014 $ / shares | Mar. 31, 2014 $ / shares | Dec. 31, 2015 USD ($) $ / shares | Dec. 31, 2014 USD ($) $ / shares | Dec. 31, 2013 USD ($) $ / shares
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Stock split declared December 20, 2013, ratio (3:2) | 1.5 |  |  |  |  |  |  |  |  |  |  |
Common stock dividends declared |  |  |  |  |  |  |  |  |  | $ 40,043 | $ 38,429 | $ 37,107
Common stock dividends declared (in dollars per share) | $ / shares |  | $ 0.295 | $ 0.295 | $ 0.283 | $ 0.283 | $ 0.283 | $ 0.283 | $ 0.272 | $ 0.272 | $ 1.16 | $ 1.11 | $ 1.07
MGE [Member] |  |  |  |  |  |  |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Cash dividends paid to parent by MGE |  |  |  |  |  |  |  |  |  | $ 30,000 | $ 26,500 | $ 25,000

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_ClassOfStockLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Aggregate dividends paid during the period for each share of common stock outstanding. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770 + Details
Name: | us-gaap_CommonStockDividendsPerShareCashPaid
Namespace Prefix: | us-gaap_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of paid and unpaid common stock dividends declared with the form of settlement in cash. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770 + Details
Name: | us-gaap_DividendsCommonStockCash
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The distributions of earnings to an entity that is affiliated with the reporting entity by means of direct or indirect ownership. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Financing Activities -URI http://asc.fasb.org/extlink&oid=6513228 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 15 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3291-108585 + Details
Name: | us-gaap_PaymentsOfDistributionsToAffiliates
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Ratio applied to the conversion of stock split, for example but not limited to, one share converted to two or two shares converted to one. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 4 -Subparagraph (SAB TOPIC 4.C) -URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187143-122770 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Stock Split -URI http://asc.fasb.org/extlink&oid=6525746 + Details
Name: | us-gaap_StockholdersEquityNoteStockSplitConversionRatio1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:pureItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | dei_LegalEntityAxis=us-gaap_SubsidiariesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |