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Consolidated Statements of Comprehensive Income (Parentheticals) - USD ($) $ in Thousands | 12 Months Ended
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Dec. 31, 2015 | Dec. 31, 2014 | Dec. 31, 2013
Unrealized (loss) gain on available-for-sale securities, taxes | $ (67) | $ 54 | $ 189
MGE [Member] |  |  |
Unrealized (loss) gain on available-for-sale securities, taxes | $ (81) | $ (33) | $ 126

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- Definition Amount of tax expense (benefit) before reclassification adjustments of unrealized holding gain (loss) on available-for-sale securities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 12 -URI http://asc.fasb.org/extlink&oid=36458714&loc=d3e640-108580 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 10A -Subparagraph (e,f) -URI http://asc.fasb.org/extlink&oid=36458714&loc=SL7669646-108580 + Details
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