Madison Gas & Electric 10-Q 7 Aug 19 2019 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2019	Jul. 31, 2019
Document And Entity Information [Line Items]
Entity Registrant Name	MGE Energy Inc
Entity Central Index Key	0001161728
Document Type	10-Q
Document Period End Date	Jun. 30, 2019
Amendment Flag	false
Trading Symbol	MGEE
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q2
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Common Stock Shares Outstanding		34,668,370
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Shell Company	false
Security Exchange Name	The Nasdaq Stock Market
Security 12(b) Title	Common Stock, $1 Par Value Per Share
Entity Tax Identification Number	392040501
Entity File Number	000-49965
Entity Incorporation State Country Code	Wisconsin
Entity Address Address Line 1	133 South Blair Street
EntityAddressCityOrTown	Madison
Entity Address State Or Province	WI
Entity Address Postal Zip Code	53788
City Area Code	608
Local Phone Number	252-7000
Document Transition Report	false
Entity Interactive Data Current	Yes
Document Quarterly Report	true
MGE [Member]
Document And Entity Information [Line Items]
Entity Registrant Name	Madison Gas and Electric Company
Entity Central Index Key	0000061339
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Entity Common Stock Shares Outstanding		17,347,894
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Shell Company	false
Entity Tax Identification Number	390444025
Entity File Number	000-1125
Entity Incorporation State Country Code	Wisconsin
Entity Address Address Line 1	133 South Blair Street
EntityAddressCityOrTown	Madison
Entity Address State Or Province	WI
Entity Address Postal Zip Code	53788
City Area Code	608
Local Phone Number	252-7000
Document Transition Report	false
Entity Interactive Data Current	Yes
Document Quarterly Report	true

MGE Energy Inc Consolidated Sta

MGE Energy Inc Consolidated Statements of Income (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Operating Revenues:
Electric revenues	$ 97,077	$ 99,282	$ 194,546	$ 194,149
Gas revenue	25,070	24,980	95,170	87,745
Total Operating Revenues	122,147	124,262	289,716	281,894
Operating Expenses:
Fuel for electric generation	10,403	15,251	24,320	27,151
Purchased power	11,036	12,979	21,887	30,012
Cost of gas sold	8,875	9,562	52,128	49,188
Other operations and maintenance	48,974	43,453	95,910	87,846
Depreciation and amortization	18,091	13,872	35,230	27,495
Other general taxes	4,985	4,914	9,948	9,783
Total Operating Expenses	102,364	100,031	239,423	231,475
Operating Income	19,783	24,231	50,293	50,419
Other income, net	5,019	4,731	9,870	9,650
Interest expense, net	(5,749)	(4,783)	(11,396)	(9,522)
Income before income taxes	19,053	24,179	48,767	50,547
Income tax provision	(3,505)	(5,828)	(9,213)	(12,195)
Net Income	$ 15,548	$ 18,351	$ 39,554	$ 38,352
Earnings Per Share of Common Stock (basic and diluted)	$ 0.45	$ 0.53	$ 1.14	$ 1.11
Dividends per share of common stock	$ 0.338	$ 0.323	$ 0.675	$ 0.645
Weighted Average Shares Outstanding (basic and diluted)	34,668	34,668	34,668	34,668

Madison Gas and Electric Compan

Madison Gas and Electric Company Consolidated Statements of Income (Unaudited) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Operating Revenues:
Electric revenues	$ 97,077,000	$ 99,282,000	$ 194,546,000	$ 194,149,000
Gas revenue	25,070,000	24,980,000	95,170,000	87,745,000
Total Operating Revenues	122,147,000	124,262,000	289,716,000	281,894,000
Operating Expenses:
Fuel for electric generation	10,403,000	15,251,000	24,320,000	27,151,000
Purchased power	11,036,000	12,979,000	21,887,000	30,012,000
Cost of gas sold	8,875,000	9,562,000	52,128,000	49,188,000
Other operations and maintenance	48,974,000	43,453,000	95,910,000	87,846,000
Depreciation and amortization	18,091,000	13,872,000	35,230,000	27,495,000
Other general taxes	4,985,000	4,914,000	9,948,000	9,783,000
Total Operating Expenses	102,364,000	100,031,000	239,423,000	231,475,000
Operating Income	19,783,000	24,231,000	50,293,000	50,419,000
Other income, net	5,019,000	4,731,000	9,870,000	9,650,000
Interest expense, net	(5,749,000)	(4,783,000)	(11,396,000)	(9,522,000)
Income before income taxes	19,053,000	24,179,000	48,767,000	50,547,000
Income tax provision	(3,505,000)	(5,828,000)	(9,213,000)	(12,195,000)
Net Income	15,548,000	18,351,000	39,554,000	38,352,000
MGE [Member]
Operating Revenues:
Electric revenues	97,077,000	99,282,000	194,546,000	194,149,000
Gas revenue	25,070,000	24,980,000	95,170,000	87,745,000
Total Operating Revenues	122,147,000	124,262,000	289,716,000	281,894,000
Operating Expenses:
Fuel for electric generation	10,403,000	15,251,000	24,320,000	27,151,000
Purchased power	11,036,000	12,979,000	21,887,000	30,012,000
Cost of gas sold	8,875,000	9,562,000	52,128,000	49,188,000
Other operations and maintenance	48,673,000	43,001,000	95,335,000	87,188,000
Depreciation and amortization	18,091,000	13,872,000	35,230,000	27,495,000
Other general taxes	4,985,000	4,914,000	9,948,000	9,783,000
Total Operating Expenses	102,063,000	99,579,000	238,848,000	230,817,000
Operating Income	20,084,000	24,683,000	50,868,000	51,077,000
Other income, net	2,958,000	2,314,000	5,165,000	4,811,000
Interest expense, net	(6,133,000)	(5,173,000)	(12,128,000)	(10,227,000)
Income before income taxes	16,909,000	21,824,000	43,905,000	45,661,000
Income tax provision	(2,966,000)	(5,221,000)	(7,892,000)	(10,802,000)
Net Income Including Noncontrolling Interest	13,943,000	16,603,000	36,013,000	34,859,000
Less Net Income Attributable to Noncontrolling Interest, net of tax	(5,621,000)	(5,505,000)	(11,111,000)	(11,311,000)
Net Income	$ 8,322,000	$ 11,098,000	$ 24,902,000	$ 23,548,000

MGE Energy Inc Consolidated S_2

MGE Energy Inc Consolidated Statements of Cash Flows (Unaudited) - USD ($)	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Operating Activities:
Net Income	$ 39,554,000	$ 38,352,000
Items not affecting cash:
Depreciation and amortization	35,230,000	27,495,000
Deferred income taxes	2,306,000	(664,000)
Provision for doubtful receivables	732,000	354,000
Employee benefit plan credit	(1,920,000)	(1,076,000)
Equity earnings in ATC	(4,515,000)	(4,441,000)
Other items	(717,000)	160,000
Changes in working capital items:
Decrease in current assets	15,349,000	29,120,000
Decrease in current liabilities	(951,000)	(1,333,000)
Dividends from ATC	3,745,000	3,905,000
Cash contributions to pension and other postretirement plans	(2,319,000)	(2,640,000)
Other noncurrent items, net	(610,000)	2,386,000
Cash Provided by Operating Activities	85,884,000	91,618,000
Investing Activities:
Capital expenditures	(79,092,000)	(100,389,000)
Capital contributions to investments	(3,386,000)	(3,280,000)
Other	(156,000)	598,000
Cash Used for Investing Activities	(82,634,000)	(103,071,000)
Financing Activities:
Cash dividends paid on common stock	(23,401,000)	(22,361,000)
Repayment of long-term debt	(2,263,000)	(2,213,000)
Proceeds from short-term debt	10,500,000	24,200,000
Other	(1,193,000)	0
Cash (Used for) Provided by Financing Activities	(16,357,000)	(374,000)
Change in cash, cash equivalents, and restricted cash	(13,107,000)	(11,827,000)
Cash, cash equivalents, and restricted cash at beginning of period	84,929,000	112,094,000
Cash, cash equivalents, and restricted cash at end of period	$ 71,822,000	$ 100,267,000

Madison Gas and Electric Comp_2

Madison Gas and Electric Company Consolidated Statements of Cash Flows (Unaudited) - USD ($)	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Items not affecting cash:
Depreciation and amortization	$ 35,230,000	$ 27,495,000
Deferred income taxes	2,306,000	(664,000)
Provision for doubtful receivables	732,000	354,000
Employee benefit plan credit	(1,920,000)	(1,076,000)
Equity earnings in MGE Transco	(4,515,000)	(4,441,000)
Other items	(717,000)	160,000
Changes in working capital items:
Decrease in current assets	15,349,000	29,120,000
Increase in current liabilities	(951,000)	(1,333,000)
Cash contributions to pension and other postretirement plans	(2,319,000)	(2,640,000)
Other noncurrent items, net	(610,000)	2,386,000
Cash Provided by Operating Activities	85,884,000	91,618,000
Investing Activities:
Capital expenditures	(79,092,000)	(100,389,000)
Capital contributions to investments	(3,386,000)	(3,280,000)
Other	(156,000)	598,000
Cash Used for Investing Activities	(82,634,000)	(103,071,000)
Financing Activities:
Repayment of long-term debt	(2,263,000)	(2,213,000)
Proceeds from short-term debt	10,500,000	24,200,000
Other	(1,193,000)	0
Cash (Used for) Provided by Financing Activities	(16,357,000)	(374,000)
Change in cash, cash equivalents, and restricted cash	(13,107,000)	(11,827,000)
Cash, cash equivalents, and restricted cash at beginning of period	84,929,000	112,094,000
Cash, cash equivalents, and restricted cash at end of period	71,822,000	100,267,000
MGE [Member]
Operating Activities:
Net Income	36,013,000	34,859,000
Items not affecting cash:
Depreciation and amortization	35,230,000	27,495,000
Deferred income taxes	1,231,000	(2,574,000)
Provision for doubtful receivables	732,000	354,000
Employee benefit plan credit	(1,920,000)	(1,076,000)
Other items	(181,000)	707,000
Changes in working capital items:
Decrease in current assets	15,845,000	28,686,000
Increase in current liabilities	1,096,000	1,943,000
Cash contributions to pension and other postretirement plans	(2,319,000)	(2,640,000)
Other noncurrent items, net	(441,000)	2,293,000
Cash Provided by Operating Activities	85,286,000	90,047,000
Investing Activities:
Capital expenditures	(79,092,000)	(100,389,000)
Other	(271,000)	(422,000)
Cash Used for Investing Activities	(79,363,000)	(100,811,000)
Financing Activities:
Distributions to parent from noncontrolling interest	(11,500,000)	(13,500,000)
Repayment of long-term debt	(2,263,000)	(2,213,000)
Proceeds from short-term debt	10,500,000	24,200,000
Other	(1,038,000)	0
Cash (Used for) Provided by Financing Activities	(4,301,000)	8,487,000
Change in cash, cash equivalents, and restricted cash	1,622,000	(2,277,000)
Cash, cash equivalents, and restricted cash at beginning of period	6,670,000	10,093,000
Cash, cash equivalents, and restricted cash at end of period	$ 8,292,000	$ 7,816,000

Consolidated Balance Sheets (Un

Consolidated Balance Sheets (Unaudited) - USD ($)	Jun. 30, 2019	Dec. 31, 2018
Current Assets:
Cash and cash equivalents	$ 69,913,000	$ 83,102,000
Accounts receivable, less reserves	35,606,000	43,593,000
Other accounts receivables, less reserves	7,573,000	6,262,000
Unbilled revenues	21,759,000	28,243,000
Materials and supplies, at average cost	25,540,000	24,093,000
Fuel for electric generation, at average cost	8,171,000	6,599,000
Stored natural gas, at average cost	6,871,000	11,303,000
Prepaid taxes	15,478,000	16,215,000
Regulatory assets - current	11,748,000	9,477,000
Assets held for sale	0	3,080,000
Other current assets	8,941,000	8,593,000
Total Current Assets	211,600,000	240,560,000
Other long-term receivables	2,319,000	2,709,000
Regulatory assets	147,507,000	145,424,000
Other deferred assets and other	15,232,000	12,488,000
Property, Plant, and Equipment:
Property, plant, and equipment, net	1,502,475,000	1,367,585,000
Finance lease assets, net, Finance lease assets	16,700,000	2,181,000
Construction work in progress	47,576,000	139,671,000
Total Property, Plant, and Equipment	1,566,751,000	1,509,437,000
Investments	82,677,000	78,000,000
Total Assets	2,026,086,000	1,988,618,000
Current Liabilities:
Long-term debt due within one year	4,605,000	4,553,000
Short-term debt	23,500,000	13,000,000
Accounts payable	40,957,000	46,158,000
Accrued interest and taxes	6,661,000	7,384,000
Accrued payroll related items	10,723,000	13,044,000
Regulatory liabilities - current	20,762,000	13,826,000
Derivative liabilities	10,670,000	8,550,000
Other current liabilities	10,347,000	14,113,000
Total Current Liabilities	128,225,000	120,628,000
Other Credits:
Deferred income taxes	235,984,000	231,952,000
Investment tax credit - deferred	772,000	818,000
Regulatory liabilities	162,564,000	165,638,000
Accrued pension and other postretirement benefits	65,347,000	67,483,000
Derivative liabilities	21,900,000	23,980,000
Finance lease liabilities	17,720,000	1,771,000
Other deferred liabilities and other	69,560,000	66,361,000
Total Other Credits	573,847,000	558,003,000
Capitalization:
Common shareholders equity	832,797,000	816,644,000
Long-term debt	491,217,000	493,343,000
Total Capitalization	1,324,014,000	1,309,987,000
Commitments and contingencies (see Footnote 9)
Total Liabilities and Capitalization	2,026,086,000	1,988,618,000
MGE [Member]
Current Assets:
Cash and cash equivalents	6,383,000	4,843,000
Accounts receivable, less reserves	35,606,000	43,593,000
Affiliate receivables	542,000	621,000
Other accounts receivables, less reserves	7,511,000	6,111,000
Unbilled revenues	21,759,000	28,243,000
Materials and supplies, at average cost	25,540,000	24,093,000
Fuel for electric generation, at average cost	8,171,000	6,599,000
Stored natural gas, at average cost	6,871,000	11,303,000
Prepaid taxes	14,586,000	15,790,000
Regulatory assets - current	11,748,000	9,477,000
Assets held for sale	0	3,080,000
Other current assets	8,906,000	8,541,000
Total Current Assets	147,623,000	162,294,000
Affiliate receivable long-term	2,912,000	3,177,000
Regulatory assets	147,507,000	145,424,000
Other deferred assets and other	16,311,000	14,142,000
Property, Plant, and Equipment:
Property, plant, and equipment, net	1,502,504,000	1,367,614,000
Finance lease assets, net, Finance lease assets	16,700,000	2,181,000
Construction work in progress	47,576,000	139,671,000
Total Property, Plant, and Equipment	1,566,780,000	1,509,466,000
Investments	533,000	388,000
Total Assets	1,881,666,000	1,834,891,000
Current Liabilities:
Long-term debt due within one year	4,605,000	4,553,000
Short-term debt	23,500,000	13,000,000
Accounts payable	40,935,000	46,165,000
Accrued interest and taxes	9,171,000	10,319,000
Accrued payroll related items	10,723,000	13,044,000
Regulatory liabilities - current	20,762,000	13,826,000
Derivative liabilities	10,670,000	8,550,000
Other current liabilities	10,347,000	11,614,000
Total Current Liabilities	130,713,000	121,071,000
Other Credits:
Deferred income taxes	207,575,000	204,616,000
Investment tax credit - deferred	772,000	818,000
Regulatory liabilities	162,564,000	165,638,000
Accrued pension and other postretirement benefits	65,347,000	67,483,000
Derivative liabilities	21,900,000	23,980,000
Finance lease liabilities	17,720,000	1,771,000
Other deferred liabilities and other	69,535,000	66,361,000
Total Other Credits	545,413,000	530,667,000
Capitalization:
Common shareholders equity	573,258,000	548,356,000
Noncontrolling interest	141,065,000	141,454,000
Total Equity	714,323,000	689,810,000
Long-term debt	491,217,000	493,343,000
Total Capitalization	1,205,540,000	1,183,153,000
Commitments and contingencies (see Footnote 9)
Total Liabilities and Capitalization	$ 1,881,666,000	$ 1,834,891,000

Consolidated Balance Sheets (_2

Consolidated Balance Sheets (Unaudited) (Parentheticals) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Receivables, Net
Reserve for uncollectible accounts receivable	$ 2,800	$ 2,614
Reserve for uncollectible other accounts receivable	478	540
MGE [Member]
Receivables, Net
Reserve for uncollectible accounts receivable	2,800	2,614
Reserve for uncollectible other accounts receivable	$ 478	$ 540

MGE Energy Inc Consolidated S_3

MGE Energy Inc Consolidated Statements of Common Equity (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income/(Loss) [Member]
Increase (Decrease) In Stockholders' Equity [Roll Forward]
Cumulative effect of new accounting principle	$ 0			$ 377	$ (377)
Beginning balance, shares at Dec. 31, 2017		34,668
Beginning balance, value at Dec. 31, 2017	778,187	$ 34,668	$ 316,268	426,874	377
Beginning balance, value - Adjusted at Dec. 31, 2017	778,187			427,251	0
Increase (Decrease) In Stockholders' Equity [Roll Forward]
Net Income	38,352			38,352
Common stock dividends declared	(22,361)			(22,361)
Ending balance, shares at Jun. 30, 2018		34,668
Ending balance, value at Jun. 30, 2018	794,178	$ 34,668	316,268	443,242	0
Beginning balance, shares at Mar. 31, 2018		34,668
Beginning balance, value at Mar. 31, 2018	787,007	$ 34,668	316,268	436,071	0
Increase (Decrease) In Stockholders' Equity [Roll Forward]
Net Income	18,351			18,351
Common stock dividends declared	(11,180)			(11,180)
Ending balance, shares at Jun. 30, 2018		34,668
Ending balance, value at Jun. 30, 2018	794,178	$ 34,668	316,268	443,242	0
Beginning balance, shares at Dec. 31, 2018		34,668
Beginning balance, value at Dec. 31, 2018	816,644	$ 34,668	316,268	465,708	0
Increase (Decrease) In Stockholders' Equity [Roll Forward]
Net Income	39,554			39,554
Common stock dividends declared	(23,401)			(23,401)
Ending balance, shares at Jun. 30, 2019		34,668
Ending balance, value at Jun. 30, 2019	832,797	$ 34,668	316,268	481,861	0
Beginning balance, shares at Mar. 31, 2019		34,668
Beginning balance, value at Mar. 31, 2019	828,950	$ 34,668	316,268	478,014	0
Increase (Decrease) In Stockholders' Equity [Roll Forward]
Net Income	15,548			15,548
Common stock dividends declared	(11,701)			(11,701)
Ending balance, shares at Jun. 30, 2019		34,668
Ending balance, value at Jun. 30, 2019	$ 832,797	$ 34,668	$ 316,268	$ 481,861	$ 0

Madison Gas and Electric Comp_3

Madison Gas and Electric Company Consolidated Statements of Common Equity (Unaudited) - USD ($) shares in Thousands	Total	MGE [Member]	Common Stock [Member]	Common Stock [Member]MGE [Member]	Additional Paid-In Capital [Member]MGE [Member]	Retained Earnings [Member]	Retained Earnings [Member]MGE [Member]	Accumulated Other Comprehensive Income/(Loss) [Member]	Accumulated Other Comprehensive Income/(Loss) [Member]MGE [Member]	Noncontrolling Interest [Member]MGE [Member]
Increase (Decrease) In Stockholders' Equity [Roll Forward]
Cumulative effect of new accounting principle	$ 0	$ 0				$ 377,000	$ (28,000)	$ (377,000)	$ 28,000
Beginning balance, shares at Dec. 31, 2017			34,668	17,348
Beginning balance, value at Dec. 31, 2017		632,774,000		$ 17,348,000	$ 192,417,000		282,135,000		(28,000)	$ 140,902,000
Beginning balance, value - Adjusted at Dec. 31, 2017	$ 778,187,000	632,774,000				$ 427,251,000	282,107,000	$ 0	0
Increase (Decrease) In Stockholders' Equity [Roll Forward]
Net Income		34,859,000					23,548,000			11,311,000
Distributions to parent from noncontrolling interest		(13,500,000)								(13,500,000)
Ending balance, shares at Jun. 30, 2018			34,668	17,348
Ending balance, value at Jun. 30, 2018		654,133,000		$ 17,348,000	192,417,000		305,655,000		0	138,713,000
Beginning balance, shares at Mar. 31, 2018			34,668	17,348
Beginning balance, value at Mar. 31, 2018		643,530,000		$ 17,348,000	192,417,000		294,557,000		0	139,208,000
Increase (Decrease) In Stockholders' Equity [Roll Forward]
Net Income		16,603,000					11,098,000			5,505,000
Distributions to parent from noncontrolling interest		(6,000,000)								(6,000,000)
Ending balance, shares at Jun. 30, 2018			34,668	17,348
Ending balance, value at Jun. 30, 2018		654,133,000		$ 17,348,000	192,417,000		305,655,000		0	138,713,000
Beginning balance, shares at Dec. 31, 2018			34,668	17,348
Beginning balance, value at Dec. 31, 2018		689,810,000		$ 17,348,000	192,417,000		338,591,000		0	141,454,000
Increase (Decrease) In Stockholders' Equity [Roll Forward]
Net Income		36,013,000					24,902,000			11,111,000
Distributions to parent from noncontrolling interest		(11,500,000)								(11,500,000)
Ending balance, shares at Jun. 30, 2019			34,668	17,348
Ending balance, value at Jun. 30, 2019		714,323,000		$ 17,348,000	192,417,000		363,493,000		0	141,065,000
Beginning balance, shares at Mar. 31, 2019			34,668	17,348
Beginning balance, value at Mar. 31, 2019		704,380,000		$ 17,348,000	192,417,000		355,171,000		0	139,444,000
Increase (Decrease) In Stockholders' Equity [Roll Forward]
Net Income		13,943,000					8,322,000			5,621,000
Distributions to parent from noncontrolling interest		(4,000,000)								(4,000,000)
Ending balance, shares at Jun. 30, 2019			34,668	17,348
Ending balance, value at Jun. 30, 2019		$ 714,323,000		$ 17,348,000	$ 192,417,000		$ 363,493,000		$ 0	$ 141,065,000

Consolidated Statements of Comm

Consolidated Statements of Common Equity (Unaudited) (Parentheticals) - $ / shares	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Consolidated Statements of Common Equity
Dividends per share of common stock	$ 0.338	$ 0.323	$ 0.675	$ 0.645

Summary of Significant Accounti

Summary of Significant Accounting Principles	6 Months Ended
	Jun. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Summary of Significant Accounting Policies. a. Basis of Presentation - MGE Energy and MGE. This report is a combined report of MGE Energy and MGE. References in this report to "MGE Energy" are to MGE Energy, Inc. and its subsidiaries. References in this report to "MGE" are to Madison Gas and Electric Company. MGE Power Elm Road and MGE Power West Campus own electric generating assets and lease those assets to MGE. Both entities are variable interest entities under applicable authoritative accounting guidance. MGE is considered the primary beneficiary of these entities as a result of contractual agreements. As a result, MGE has consolidated MGE Power Elm Road and MGE Power West Campus. See Footnote 3 of Notes to Consolidated Financial Statements under Item 8, Financial Statements and Supplementary Data, of MGE Energy's and MGE's 2018 Annual Report on Form 10-K (the 2018 Annual Report on Form 10-K). The accompanying consolidated financial statements as of June 30, 2019, and for the three and six months ended, are unaudited but include all adjustments that MGE Energy and MGE management consider necessary for a fair statement of their respective financial statements. All adjustments are of a normal, recurring nature except as otherwise disclosed. The year-end consolidated balance sheet information was derived from the audited balance sheet appearing in the 2018 Annual Report on Form 10-K, but does not include all disclosures required by accounting principles generally accepted in the United States of America. These notes should be read in conjunction with the financial statements and the notes on pages 62 through 106 of the 2018 Annual Report on Form 10-K. b. Cash, Cash Equivalents, and Restricted Cash – MGE Energy and MGE. The following table presents the components of total cash, cash equivalents, and restricted cash on the consolidated balance sheets. MGE Energy MGE June 30, December 31, June 30, December 31, (In thousands) 2019 2018 2019 2018 Cash and cash equivalents $ 69,913 $ 83,102 $ 6,383 $ 4,843 Restricted cash 605 634 605 634 Receivable - margin account 1,304 1,193 1,304 1,193 Cash, cash equivalents, and restricted cash $ 71,822 $ 84,929 $ 8,292 $ 6,670

Adoption of Accounting Principl

Adoption of Accounting Principles and Recently Issued Accounting Pronouncements	6 Months Ended
	Jun. 30, 2019
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
New Accounting Pronouncements	New Accounting Standards - MGE Energy and MGE. Recently Adopted Leases. In February 2016, the FASB issued authoritative guidance within the codification's Leases topic that provides guidance on the classification, recognition, measurement, and disclosure of leases. The new leasing standard establishes that a lease conveys the right to control the use of identified property, plant, or equipment for a period of time in exchange for consideration. Under the new guidance, lessees are required to recognize all leases with terms greater than one year, including operating leases, on the balance sheet by recording a right-of-use asset and lease liability. Prior to the authoritative guidance, only capital leases were recognized on the balance sheet by lessees. The new accounting guidance, as applied by lessors, is materially consistent with current GAAP. In January 2018, the FASB issued authoritative guidance which provided an optional practical expedient to grandfather the accounting for existing and expired land easements not accounted for as a lease under the new authoritative guidance. MGE Energy and MGE adopted this practical expedient. The lease authoritative guidance became effective January 1, 2019. MGE Energy and MGE adopted the standard upon the effective date. In compliance with authorized transition guidance, MGE Energy and MGE began applying the new standard on January 1, 2019, but will continue to present periods prior to that date according to the previous authoritative standard. There was no material impact on the consolidated net income or cash flows. See Footnote 3 for further lease information.

Leases

Leases	6 Months Ended
	Jun. 30, 2019
Leases [Abstract]
Leases	Leases - MGE Energy and MGE. As part of its regular operations, MGE enters into various contracts related to IT equipment, substations, cell towers, land, wind easements, and other property in use for operations. A contract is or contains a lease if the contract conveys the right to control the use of identified property, plant, or equipment for a period of time in exchange for consideration. Determination as to whether an arrangement is or contains a lease is completed at inception. Leases with an initial term of 12 months or less are not recorded on the consolidated balance sheets; lease expense for these leases are recognized on a straight-line basis over the lease term. Leases with initial terms in excess of 12 months are recorded as operating or financing leases on the consolidated balance sheets. Operating lease assets and operating lease liabilities are recognized based on the present value of the future minimum lease payments over the lease term at commencement date. For leases that do not provide an implicit rate, a collateralized incremental borrowing rate based on the information available at commencement date, including lease term, is used in determining the present value of future payments. The operating lease asset also includes any lease payments made and excludes lease incentives and initial direct costs incurred. Lease terms may include options to extend or terminate the lease when it is reasonably certain that the option will be exercised. Operating lease expense is recognized on a straight-line basis over the lease term. MGE has regulatory treatment and recognizes regulatory assets or liabilities for timing differences between when net lease costs are recorded and when costs are recognized. As of June 30, 2019, MGE has no significant leases not yet commenced that would create significant future rights and obligations. The following table shows lease expense for the three and six months ended June 30, 2019: (In thousands) Three Months Ended Six Months Ended Income Statement Location Finance lease expense: Amortization of leased assets $ 437 $ 870 Depreciation and amortization Interest on lease liabilities 200 398 Interest expense, net Operating lease expense 33 60 Other operations and maintenance Total lease expense $ 670 $ 1,328 The following table shows the lease assets and liabilities on the consolidated balance sheet as of June 30, 2019: (In thousands) Balance Sheet Location Lease assets: Finance lease assets $ 16,700 Finance lease assets Operating lease assets 216 Other deferred assets and other Total lease assets $ 16,916 Lease liabilities: Finance lease liabilities - current $ 1,007 Other current liabilities Finance lease liabilities - long-term 17,720 Finance lease liabilities Operating lease liabilities - current 104 Other current liabilities Operating lease liabilities - long-term 144 Other deferred liabilities and other Total lease liabilities $ 18,975 The following table shows other financial lease information for the six months ended June 30, 2019: (In thousands) Cash paid for amounts included in the measurement of lease liabilities: Finance leases - Financing cash flows $ 643 Finance leases - Operating cash flows 398 Operating leases - Operating cash flows 71 Lease assets obtained in exchange for lease liabilities: Finance leases 12,081 Operating leases 125 The following table shows the weighted average remaining lease terms and discounts as of June 30, 2019: Weighted-average remaining lease terms (in years): Finance leases 38 Operating leases 6 Weighted-average discount rates: Finance leases 4.36 % Operating leases 3.97 % The following table shows maturities of lease liabilities as of June 30, 2019: (In thousands) Finance Operating 2019 $ 876 $ 54 2020 1,644 113 2021 1,428 46 2022 1,309 13 2023 1,228 2 Thereafter 41,316 52 Subtotal 47,801 280 Less: Present value discount ( 29,074) ( 32) Lease Liability $ 18,727 $ 248 Future minimum rental payments as of December 31, 2018, under agreements classified as operating leases with noncancelable terms in excess of one year are as follows: (In thousands) 2019 2020 2021 2022 2023 Thereafter Minimum lease payments $ 1,646 $ 1,371 $ 1,095 $ 989 $ 975 $ 22,707

Investment in ATC and ATC Holdc

Investment in ATC and ATC Holdco	6 Months Ended
	Jun. 30, 2019
Equity Method Investments and Joint Ventures [Abstract]
Investment in ATC and ATC Holdco	Investment in ATC and ATC Holdco - MGE Energy and MGE. ATC owns and operates electric transmission facilities primarily in Wisconsin. MGE received an interest in ATC when it, like other Wisconsin electric utilities, contributed its electric transmission facilities to ATC as required by Wisconsin law. That interest is presently held by MGE Transco, which, since December 1, 2016, is owned by MGE Energy. ATC Holdco was formed by several members of ATC, including MGE Energy, to pursue electric transmission development and investments outside of Wisconsin. The ownership interest in ATC Holdco is held by MGEE Transco, a wholly-owned subsidiary of MGE Energy. MGE Transco and MGEE Transco have accounted for their investments in ATC and ATC Holdco, respectively, under the equity method of accounting. Equity earnings from investments are recorded as " Other income " on the consolidated statements of income of MGE Energy. MGE Transco recorded the following: Three Months Ended Six Months Ended June 30, June 30, (In thousands) 2019 2018 2019 2018 Equity earnings from investment in ATC $ 2,297 $ 1,990 $ 4,515 $ 4,441 Dividends from ATC (a) 1,733 2,959 3,745 2,959 Capital contributions to ATC 1,065 1,065 1,243 1,775 (a) MGE Transco recorded a $ 2.3 million dividend receivable from ATC as of December 31, 2017. A cash dividend was received in January of the proceeding year. MGE Transco recorded a $ 1.4 million dividend receivable from ATC as of June 30, 2018. A cash dividend was received in July 2018. ATC Holdco was formed in December 2016. In the near term, it is expected that ATC Holdco will be pursuing transmission development opportunities that typically have long development and investment lead times before becoming operational. In July 2019, MGE Transco made a $ 0.9 million capital contribution to ATC. ATC ' s summarized financial data is as follows: Three Months Ended Six Months Ended June 30, June 30, (In thousands) 2019 2018 2019 2018 Operating revenues $ 182,212 $ 165,506 $ 359,927 $ 330,935 Operating expenses ( 93,573) ( 91,474) ( 183,960) ( 176,367) Other income, net 287 1,520 547 1,631 Interest expense, net ( 28,838) ( 26,895) ( 57,956) ( 54,657) Earnings before members' income taxes $ 60,088 $ 48,657 $ 118,558 $ 101,542 MGE receives transmission and other related services from ATC. During the three and six months ended June 30, 2019, MGE recorded $ 7.6 million and $ 15.2 million, respectively, for transmission services received compared to $ 7.2 million and $ 14.4 million for the comparable periods in 2018. MGE also provides a variety of operational, maintenance, and project management services for ATC, which is reimbursed by ATC. As of June 30, 2019, and December 31, 2018, MGE had a receivable due from ATC of $ 0.6 million and $ 0.1 million, respectively.

Taxes

Taxes	6 Months Ended
	Jun. 30, 2019
Income Tax Disclosure [Abstract]
Taxes	Taxes - MGE Energy and MGE. Effective Tax Rate. The consolidated income tax provision differs from the amount computed by applying the statutory federal income tax rate to income before income taxes, as follows: MGE Energy MGE Three Months Ended June 30, 2019 2018 2019 2018 Statutory federal income tax rate 21.0% 21.0% 21.0% 21.0% State income taxes, net of federal benefit 6.3% 6.3% 6.2% 6.2% Amortized investment tax credits ( 0.1% ( 0.1% ( 0.1% ( 0.1% Credit for electricity from wind energy (a) ( 6.2% ( 0.4% ( 6.8% ( 0.4% AFUDC equity, net ( 0.2% ( 1.1% ( 0.2% ( 1.1% Amortization of utility excess deferred tax - tax reform (b) ( 2.4% ( 1.9% ( 2.6% ( 1.9% Other, net, individually insignificant -% 0.3% 0.1% 0.2% Effective income tax rate 18.4% 24.1% 17.6% 23.9% MGE Energy MGE Six Months Ended June 30, 2019 2018 2019 2018 Statutory federal income tax rate 21.0% 21.0% 21.0% 21.0% State income taxes, net of federal benefit 6.3% 6.3% 6.2% 6.2% Amortized investment tax credits ( 0.1% ( 0.1% ( 0.1% ( 0.1% Credit for electricity from wind energy (a) ( 6.1% ( 0.3% ( 6.7% ( 0.3% AFUDC equity, net ( 0.2% ( 0.9% ( 0.2% ( 1.0% Amortization of utility excess deferred tax - tax reform (b) ( 2.4% ( 1.9% ( 2.6% ( 2.1% Other, net, individually insignificant 0.4% -% 0.4% -% Effective income tax rate 18.9% 24.1% 18.0% 23.7% (a) Saratoga Wind Farm became operational in February 2019. (b) Included are impacts of the Tax Cuts and Jobs Act for the regulated utility for excess deferred taxes recognized using a normalization method of accounting. For the three and six months ended June 30, 2019 , MGE recognized $ 0.5 million and $ 1.1 million, respectively, compared to $ 0.4 million and $ 0.9 million for the comparable periods in 2018. The amount and timing of the cash impacts will depend on the period over which certain income tax benefits are provided to customers, determined by the PSCW.

Pension and Other Postretiremen

Pension and Other Postretirement Plans	6 Months Ended
	Jun. 30, 2019
Compensation and Retirement Disclosure [Abstract]
Pension and Other Postretirement Plans	Pension and Other Postretirement Plans - MGE Energy and MGE. MGE maintains qualified and nonqualified pension plans, health care, and life insurance benefits. Additionally, MGE has defined contribution 401(k) benefit plans. The components of net periodic benefit cost, other than the service cost component, are recorded in " Other income, net " on the consolidated statements of income. The service cost component is recorded in " Other operations and maintenance " on the consolidated statements of income. The service cost component of net periodic benefit cost is eligible for capitalization within the consolidated balance sheets. MGE has regulatory treatment and recognizes regulatory assets or liabilities for timing differences between when net periodic benefit costs are recovered and when costs are recognized. The following table presents the components of net periodic benefit costs recognized. Three Months Ended Six Months Ended June 30, June 30, (In thousands) 2019 2018 2019 2018 Pension Benefits Components of net periodic benefit cost: Service cost $ 1,221 $ 1,404 $ 2,362 $ 2,861 Interest cost 3,742 3,222 7,194 6,430 Expected return on assets ( 5,922) ( 6,552) ( 11,469) ( 13,120) Amortization of: Prior service credit ( 31) ( 11) ( 59) ( 22) Actuarial loss 1,985 1,341 3,714 2,639 Net periodic benefit (credit) cost $ 995 $ ( 596) $ 1,742 $ ( 1,212) Postretirement Benefits Components of net periodic benefit cost: Service cost $ 334 $ 310 $ 553 $ 642 Interest cost 865 648 1,442 1,306 Expected return on assets ( 676) ( 814) ( 1,357) ( 1,616) Amortization of: Transition obligation 1 - 2 1 Prior service credit ( 662) ( 667) ( 1,330) ( 1,334) Actuarial loss 94 116 200 244 Net periodic benefit (credit) cost $ ( 44) $ ( 407) $ ( 490) $ ( 757) As a result of lower investment returns in the fourth quarter of 2018, pension and postretirement benefit costs increased in 2019. In July 2019, the PSCW approved MGE’s request to defer the difference between estimated pension and other postretirement costs included in the 2019 and 2020 rate settlement and actual expense incurred up to $ 5.9 million. MGE expects that the deferred cost for employee benefit plans will be factored into future rate actions starting in 2021. For the three and six months ended June 30, 2019, MGE has deferred approximately $ 3

Equity and Financing Arrangemen

Equity and Financing Arrangements	6 Months Ended
	Jun. 30, 2019
Equity and Financing Arrangements Disclosure [Abstract]
Equity and Financing Arrangements	Equity and Financing Arrangements - MGE Energy. a. Common Stock. MGE Energy sells shares of its common stock through its Stock Plan. Those shares may be newly issued shares or shares that MGE Energy has purchased in the open market for resale to participants in the Stock Plan. All sales under the Stock Plan are covered by a shelf registration statement that MGE Energy filed with the SEC. For both the three and six months ended June 30, 2019 and 2018, MGE Energy did not issue any new shares b. Dilutive Shares Calculation. MGE Energy does not

Share-Based Compensation

Share-Based Compensation	6 Months Ended
	Jun. 30, 2019
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-Based Compensation	Share-Based Compensation - MGE Energy and MGE. Under MGE Energy ' s Director Incentive Plan and its Performance Unit Plan, non-employee directors and eligible employees, respectively, may receive performance units that entitle the holder to receive a cash payment equal to the value of a designated number of shares of MGE Energy's common stock, plus dividend equivalent payments thereon, at the end of the performance period set in the award. In 2019, 5,175 units were granted under the Director Incentive Plan and are subject to a three 17,022 units were granted under the Performance Unit Plan and are subject to a five required by applicable accounting standards. Changes in fair value as well as the original grant are recognized as compensation cost. Since this amount is remeasured throughout the vesting period, the compensation cost is subject to variability. For nonretirement eligible employees under the Performance Unit Plan, stock-based compensation costs are accrued and recognized using the graded vesting method. Compensation cost for retirement eligible employees or employees that will become retirement eligible during the vesting schedule are recognized on an abridged horizon as retirement eligibility accelerates vesting. During the three and six months ended June 30, 2019, MGE recorded $ 0.7 million and $ 1.9 million, respectively, in compensation expense as a result of awards under the plans compared to $ 0.8 million and $ 1.0 million for the comparable periods in 2018. In January 2019, cash payments of $ 1.5 million were distributed relating to awards that were granted in a prior year under the plans. No for fei tur es o units occurred during 5.7 million of outstanding awards are vested. Of this amount, no cash settlements have occurred as cash payments are only made at the end of the period covered by the awards.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies. a. Environmental - MGE Energy and MGE. MGE Energy and MGE are subject to frequently changing local, state, and federal regulations concerning air quality, water quality, land use, threatened and endangered species, hazardous materials handling, and solid waste disposal. These regulations affect the manner in which they conduct their operations, the costs of those operations, as well as capital and operating expenditures. Several of these environmental rules are subject to legal challenges, reconsideration and/or other uncertainties. Regulatory initiatives, proposed rules, and court challenges to adopted rules have the potential to have a material effect on capital expenditures and operating costs. Management believes compliance costs will be recovered in future rates based on previous treatment of environmental compliance projects. These initiatives, proposed rules, and court challenges include: • The EPA's published water effluent limitations guidelines and standards for steam electric power plants, which focus on the reduction of metals and other pollutants in wastewater from new and existing power plants, such as the coal-burning plants at Columbia and the Elm Road Units. The operators of the Columbia and the Elm Road Units have indicated that equipment upgrades may be necessary to comply with the new discharge standards. Management believes that any compliance costs will be recovered in future rates based on previous treatment of environmental compliance projects. • The EPA's cooling water intake rules, which require cooling water intake structures at electric power plants, such as our Blount and Columbia plants, to meet best available technology standards so that mortality from entrainment (drawing aquatic life into a plant's cooling system) and impingement (trapping aquatic life on screens) are reduced. MGE expects that the rule will not have a material effect on its existing plants. • Greenhouse Gas (GHG) reduction guidelines and approval criteria established under the Clean Air Act (CAA) for states to use in developing plans to control GHG emissions from existing fossil fuel-fired electric generating units (EGUs). In 2015, the EPA finalized the Clean Power Plan (CPP), which directed states to submit plans to reduce GHG emissions from the electric generation sector. The CPP applies the statutory requirements for the "best system of emission reduction" (BSER) broadly so as to encompass GHG emission reduction strategies that extend "beyond the fenceline" of existing EGUs and requires a shift in the energy generation mix at the grid level. In February 2016, the U.S. Supreme Court stayed implementation of the CPP while the United States Court of Appeals for the D.C. Circuit reviews the rule. The D.C. Circuit agreed to hold its review of the CPP in abeyance while the EPA reconsidered the CPP. The stay and abeyance order remain in effect. If ultimately upheld, the CPP could have a material effect on MGE’s operations. In July 2019, the EPA published a final rule repealing the CPP and creating the replacement Affordable Clean Energy (ACE) rule to reduce greenhouse gas emissions from existing EGUs. The ACE rule applies to EGUs greater than 25 MW. Based upon these criteria, the ACE rule will likely apply to Columbia and the Elm Road Units. EGUs that burn fossil fuels other than coal, such as Blount, WCCF, and smaller natural gas- and diesel-fueled units are not subject to the ACE rule. In contrast to the CPP, the ACE rule limits BSER to only "inside the fenceline" heat rate improvement technologies or systems that can be applied at an affected coal fired EGU. Under ACE, states have the primary role in developing standards of performance that result from the application of BSER. The EPA has not provided a standard of performance that it will deem presumptively acceptable in a state plan, but urges states to provide full justification for each component of their plans so that the EPA can evaluate BSER on a unit-by-unit basis. States will have three years to develop and submit compliance plans to the EPA. The EPA will have a year to review and approve the plans. The states are given 24 months from the approval date to implement the rule and can extend the compliance schedule for units that meet progress milestones. EGU’s compliance with the ACE rule may not be required until 2024 or later. MGE is currently evaluating how this rule may impact operations. Until the State of Wisconsin develops a plan that is accepted by the EPA, MGE will not be able to determine the final impact of the rule. MGE will continue to evaluate the rule and monitor ongoing and potential legal proceedings associated with the CPP and ACE rules. • The EPA's rule to regulate ambient levels of ozone through the 2015 Ozone National Ambient Air Quality Standards (NAAQS). In May 2018, the EPA issued a final rule which designated the northeast portion of Milwaukee County as being in nonattainment with this NAAQS. The Elm Road Units are located in Milwaukee County, outside the designated nonattainment area. In August 2018, several environmental groups, the City of Chicago, and the State of Illinois filed federal lawsuits challenging several of the EPA's attainment designation decisions, including the partial Milwaukee County designation as being too narrow and not sufficiently protective. MGE is monitoring the outcome of this lawsuit and how it may affect our Elm Road Units in Milwaukee County. At this time, MGE expects that the 2015 Ozone NAAQS will not have a material effect on its existing plants based on final designations. • Rules regulating nitrogen oxide (NO x 2 MGE has met our CSAPR obligations in 2018 and 2017 through a combination of reduced emissions through pollution control (e.g. SCR installation at Columbia), as well as owned, received, and purchased allowances. There remains uncertainty around CSAPR due to legal challenges, however, MGE expects that we will meet ongoing CSAPR obligations for the foreseeable future. MGE will continue to monitor developments and litigation to this rule. Columbia is subject to the best available retrofit technology (BART) regulations, a subsection of the EPA's CAVR, which may require pollution control retrofits. Columbia's existing pollution control upgrades, and the EPA's stance that compliance with the CSAPR equals compliance with BART, should mean that Columbia will not need to do additional work to meet BART requirements. At this time, however, the BART regulatory obligations, compliance strategies, and costs remain uncertain in Wisconsin due to the continued legal challenges surrounding CSAPR and CAVR. MGE will continue to monitor developments to this rule. • The EPA's Coal Combustion Residuals Rule (CCR), which regulates coal ash from burning coal for the purpose of generating electricity as a solid waste, and defines what ash use activities would be considered generally exempt beneficial reuse of coal ash. The CCR rule also regulates landfills, ash ponds, and other surface impoundments used for coal combustion residuals by regulating their design, location, monitoring, and operation. Review of the Elm Road Units has indicated that the costs to comply with this rule are not expected to be significant. Columbia's operator has completed a review of their system and has determined that an onsite ash pond will need to be closed and replaced with a dry ash handling system. The dry ash handling system installation is planned for 2020-2021. In July 2018, the EPA published a final rule that included amendments to the CCR (which include the allowance of alternative performance standards for landfills and surface impoundments, revised risk-based groundwater protection standards, and an extension of the deadline by which certain facilities must cease the placement of waste in CCR units). In August 2018, the Court of Appeals for the D.C. Circuit vacated parts of the CCR for not being sufficiently protective of the environment. It is unclear how the EPA will respond to that decision. MGE will continue to monitor potential rule modifications to assess potential impacts on operations. b. Legal Matters - MGE Energy and MGE. MGE is involved in various legal matters that are being defended and handled in the normal course of business. MGE maintains accruals for such costs that are probable of being incurred and subject to reasonable estimation. The accrued amount for these matters is not material to the financial statements. MGE does not expect the resolution of these matters to have a material adverse effect on its consolidated results of operations, financial condition, or cash flows. c. Purchase Contracts - MGE Energy and MGE. MGE Energy and MGE have entered into various commodity supply, transportation, and storage contracts to meet their obligations to deliver electricity and natural gas to customers. Management expects to recover these costs in future customer rates. The following table shows future commitments related to purchase contracts as of June 30, 2019: (In thousands) 2019 2020 2021 2022 2023 Thereafter Natural gas Transportation and storage (a) 10,102 21,700 21,432 21,432 21,432 54,663 Supply (b) 8,822 10,280 - - - - Solar farms (c) 74 147 2,572 156 160 10,474 Other 92 928 929 97 99 1,079 $ 19,090 $ 33,055 $ 24,933 $ 21,685 $ 21,691 $ 66,216 (a) MGE's natural gas transportation and storage contracts require fixed monthly payments for firm supply pipeline transportation and storage capacity. The pricing components of the fixed monthly payments for the transportation and storage contracts are established by FERC but may be subject to change. (b) These commitments include market-based pricing. (c) In July 2019 MGE entered into additional commitments related to operations of the Badger Hollow Solar Farm. The total of these commitments by year are as follows: $ 0.5 million in 2019, $ 0.2 million in 2020, $ 0.5 million in 2021, $ 0.6 million in 2022, $ 0.6 million in 2023, and $ 22.0 million thereafter. d. Capital Purchase Commitments - MGE Energy and MGE. Various contractual obligations contain minimum future commitments related to capital expenditures for certain construction projects, including the Two Creeks solar project and the Badger Hollow Solar Farm. As of June 30, 2019, the Two Creeks future minimum construction commitment is $ 52.8 million. In July 2019 MGE entered into an additional future minimum construction commitment of $ 59.9 million related to Badger Hollow. See Footnote 14 for more information.

Rate Matters

Rate Matters	6 Months Ended
	Jun. 30, 2019
Regulated Operations [Abstract]
Rate Matters	Rate Matters - MGE Energy and MGE. a. Rate Proceedings. In December 2018, the PSCW approved the settlement agreement between MGE and intervening parties in the rate case. The settlement decreases electric rates by 2.24%, or $ 9.2 million, in 2019. MGE will maintain 1.06%, or $ 1.7 million, in 2019 and 1.46%, or $ 2.4 million, in 2020. The gas increase covers infrastructure costs. It also reflects the impacts of the Tax Act. The return on common stock equity for 2019 and 2020 9.8% based on a capital structure consisting of 56.6% common equity in 2019 and 56.1% common equity in 2020 . MGE did not file a base rate case for 2018. b. Fuel Rules. Fuel rules require the PSCW and Wisconsin utilities to defer electric fuel-related costs that fall outside a symmetrical cost tolerance band around the amount approved for a utility in its annual fuel proceedings. Any over/under recovery of the actual costs is determined in the following year and is then reflected in future billings to electric retail customers. The fuel rules bandwidth is currently set at plus or minus 2%. Under fuel rules, MGE would defer costs, less any excess revenues, if its actual electric fuel costs exceeded 102% of the electric fuel costs allowed in its latest rate order. Excess revenues are defined as revenues in the year in question that provide MGE with a greater return on common equity than authorized by the PSCW in MGE's latest rate order. Conversely, MGE is required to defer the benefit of lower costs if actual electric fuel costs were less than 98% of the electric fuel costs allowed in that order. These costs will be subject to the PSCW's annual review of fuel costs completed in the year following the deferral. In December 2017, the PSCW approved a surcharge for 2018 electric fuel-related costs. The surcharge increased electric retail revenue in 2018 by $ 0.5 million, or 0.13%. In July 2019, the PSCW issued a final decision in the 2018 fuel rules proceedings for MGE to refund additional fuel savings incurred to its retail electric customers over a one-month period. MGE will return $ 9.5 million plus accrued interest in October 2019. There was no change to the refund in the fuel rules proceedings from the amount MGE deferred in the previous year. As of June 30, 2019, MGE had no $ 9.5 million of 2018 fuel savings .

Derivative and Hedging Instrume

Derivative and Hedging Instruments	6 Months Ended
	Jun. 30, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative and Hedging Instruments	Derivative and Hedging Instruments - MGE Energy and MGE. a. Purpose. As part of its regular operations, MGE enters into contracts, including options, swaps, futures, forwards, and other contractual commitments, to manage its exposure to commodity prices. To the extent that these contracts are derivatives, MGE assesses whether or not the normal purchases or normal sales exclusion applies. For contracts to which this exclusion cannot be applied, the derivatives are recognized in the consolidated balance sheets at fair value. MGE's financial commodity derivative activities are conducted in accordance with its electric and gas risk management program, which is approved by the PSCW and limits the volume MGE can hedge with specific risk management strategies. The maximum length of time over which cash flows related to energy commodities can be hedged is four net loss or net gain position, respectively. The deferred gain or loss is recognized in earnings in the delivery month applicable to the instrument. Gains and losses related to hedges qualifying for regulatory treatment are recoverable in gas rates through the PGA or in electric rates as a component of the fuel rules mechanism. b. Notional Amounts. The gross notional volume of open derivatives is as follows: June 30, 2019 December 31, 2018 Commodity derivative contracts 507,720 MWh 386,440 MWh Commodity derivative contracts 7,140,000 Dth 5,260,000 Dth FTRs 5,853 MW 2,252 MW PPA 1,750 MW 2,050 MW c. Financial Statement Presentation. MGE purchases and sells exchange-traded and over-the-counter options, swaps, and future contracts. These arrangements are primarily entered into to help stabilize the price risk associated with gas or power purchases. These transactions are employed by both MGE's gas and electric segments. Additionally, as a result of the firm transmission agreements that MGE holds on electricity transmission paths in the MISO market, MGE holds financial transmission rights (FTRs). An FTR is a financial instrument that entitles the holder to a stream of revenues or charges based on the differences in hourly day-ahead energy prices between two points on the transmission grid. The fair values of these instruments are offset with a corresponding regulatory asset/liability depending on whether they are in a net loss/gain position. Depending on the nature of the instrument, the gain or loss associated with these transactions will be reflected as cost of gas sold, fuel for electric generation, or purchased power expense in the delivery month applicable to the instrument. As of June 30, 2019, the cost basis of exchange traded derivatives and FTRs exceeded their fair value by $ 0.9 million. As of December 31, 2018, the fair value of exchange traded derivatives and FTRs exceeded their cost basis by and $ 0.7 million. MGE is a party to a purchased power agreement that provides MGE with firm capacity and energy during a base term from June 1, 2012, through May 31, 2022. The agreement also allows MGE an option to extend the contract after the base term. The agreement is accounted for as a derivative contract and is recognized at its fair value on the consolidated balance sheets. However, the derivative qualifies for regulatory deferral and is recognized with a corresponding regulatory asset or liability depending on whether the fair value is in a loss or gain position. The fair value of the contract as of June 30, 2019, and December 31, 2018, reflects a loss position of $ 32.6 million and $ 32.5 million, respectively. The actual cost will be recognized in purchased power expense in the month of purchase. The following table summarizes the fair value of the derivative instruments on the consolidated balance sheets. All derivative instruments in this table are presented on a gross basis and are calculated prior to the netting of instruments with the same counterparty under a master netting agreement as well as the netting of collateral. For financial statement purposes, instruments are netted with the same counterparty under a master netting agreement as well as the netting of collateral. As of June 30, 2019, and December 31, 2018, the receivable margin account balance of $1.3 million and $1.2 million, respectively, is shown net of any collateral posted against derivative positions. Derivative Derivative (In thousands) Assets Liabilities Balance Sheet Location June 30, 2019 Commodity derivative contracts $ 578 $ 1,322 Other current assets (a) Commodity derivative contracts 81 713 Other deferred charges (a) FTRs 430 - Other current assets PPA N/A 10,670 Derivative liability (current) PPA N/A 21,900 Derivative liability (long-term) December 31, 2018 Commodity derivative contracts $ 727 $ 270 Other current assets Commodity derivative contracts 74 72 Other deferred charges FTRs 241 - Other current assets PPA N/A 8,550 Derivative liability (current) PPA N/A 23,980 Derivative liability (long-term) (a) As of June 30, 2019, collateral of $0 million was posted against and netted with derivative liability positions on the consolidated balance sheets. No collateral was posted against derivative positions as of December 31, 2018. The following tables show the effect of netting arrangements for recognized derivative assets and liabilities that are subject to a master netting arrangement or similar arrangement on the consolidated balance sheets. Offsetting of Derivative Assets (In thousands) Gross Amounts Gross Amounts Offset in Balance Sheets Collateral Posted Against Derivative Positions Net Amount Presented in Balance Sheets June 30, 2019 Commodity derivative contracts $ 659 $ ( 343) $ - $ 316 FTRs 430 - - 430 December 31, 2018 Commodity derivative contracts $ 801 $ ( 342) $ - $ 459 FTRs 241 - - 241 Offsetting of Derivative Liabilities (In thousands) Gross Amounts Gross Amounts Offset in Balance Sheets Collateral Posted Against Derivative Positions Net Amount Presented in Balance Sheets June 30, 2019 Commodity derivative contracts $ 2,035 $ ( 343) $ ( 1,692) $ - PPA 32,570 - - 32,570 December 31, 2018 Commodity derivative contracts $ 342 $ ( 342) $ - $ - PPA 32,530 - - 32,530 The following tables summarize the unrealized and realized gains (losses) related to the derivative instruments on the consolidated balance sheets and the consolidated statements of income. 2019 2018 (In thousands) Current and Long-Term Regulatory Asset Other Current Assets Current and Long-Term Regulatory Asset Other Current Assets Three Months Ended June 30: Balance at April 1, $ 31,023 $ 259 $ 41,241 $ 319 Unrealized gain 3,228 - ( 4,027) - Realized (loss) gain reclassified to a deferred account ( 731) 731 ( 363) 363 Realized (loss) gain reclassified to income statement ( 4) ( 112) 73 ( 42) Balance as of June 30, $ 33,516 $ 878 $ 36,924 $ 640 Six Months Ended June 30: Balance at January 1, $ 31,830 $ 377 $ 41,958 $ 806 Unrealized gain 2,306 - ( 3,899) - Realized (loss) gain reclassified to a deferred account ( 991) 991 ( 521) 521 Realized (loss) gain reclassified to income statement 371 ( 490) ( 614) ( 687) Balance as of June 30, $ 33,516 $ 878 $ 36,924 $ 640 Realized Losses (Gains) 2019 2018 (In thousands) Fuel for Electric Generation/ Purchased Power Cost of Gas Sold Fuel for Electric Generation/ Purchased Power Cost of Gas Sold Three Months Ended June 30: Commodity derivative contracts $ 299 $ 99 $ ( 190) $ 22 FTRs 61 - ( 300) - PPA ( 343) - 437 - Six Months Ended June 30: Commodity derivative contracts $ 568 $ 377 $ 184 $ 637 FTRs ( 74) - ( 475) - PPA ( 752) - 955 - MGE's commodity derivative contracts, FTRs, and PPA are subject to regulatory deferral. These derivatives are marked to fair value and are offset with a corresponding regulatory asset or liability. Realized gains and losses are deferred on the consolidated balance sheets and are recognized in earnings in the delivery month applicable to the instrument. As a result of the above described treatment, there are no unrealized gains or losses that flow through earnings. The PPA has a provision that may require MGE to post collateral if MGE's debt rating falls below investment grade (i.e., below BBB-). The amount of collateral that it may be required to post varies from $ 20.0 million to $ 40.0 million, depending on MGE's nominated capacity amount. As of June 30, 2019, no No counterparties Nonperformance of counterparties to the non-exchange traded derivatives could expose MGE to credit loss. However, MGE enters into transactions only with companies that meet or exceed strict credit guidelines, and it monitors these counterparties on an ongoing basis to mitigate nonperformance risk in its portfolio. As of June 30, 2019, no

Fair Value of Financial Instrum

Fair Value of Financial Instruments	6 Months Ended
	Jun. 30, 2019
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	Fair Value of Financial Instruments - MGE Energy and MGE. Fair value is defined as the price that would be received to sell an asset or would be paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants at the measurement date. The accounting standard clarifies that fair value should be based on the assumptions market participants would use when pricing the asset or liability including assumptions about risk. The standard also establishes a three-level fair value hierarchy based upon the observability of the assumptions used and requires the use of observable market data when available. The levels are: Level 1 - Pricing inputs are quoted prices within active markets for identical assets or liabilities. Level 2 - Pricing inputs are quoted prices within active markets for similar assets or liabilities; quoted prices for identical or similar instruments in markets that are not active; and model-derived valuations that are correlated with or otherwise verifiable by observable market data. Level 3 - Pricing inputs are unobservable and reflect management's best estimate of what market participants would use in pricing the asset or liability. a. Fair Value of Financial Assets and Liabilities Recorded at the Carrying Amount. The carrying amount of cash, cash equivalents, and outstanding commercial paper approximates fair market value due to the short maturity of those investments and obligations. The estimated fair market value of long-term debt is based on quoted market prices for similar financial instruments. Since long-term debt is not traded in an active market, it is classified as Level 2. The estimated fair market value of financial instruments are as follows: June 30, 2019 December 31, 2018 (In thousands) Carrying Amount Fair Value Carrying Amount Fair Value MGE Energy Assets: Cash and cash equivalents $ 69,913 $ 69,913 $ 83,102 $ 83,102 Liabilities: Short-term debt - commercial paper 23,500 23,500 13,000 13,000 Long-term debt (a) 500,168 562,969 502,431 518,811 MGE Assets: Cash and cash equivalents $ 6,383 $ 6,383 $ 4,843 $ 4,843 Liabilities: Short-term debt - commercial paper 23,500 23,500 13,000 13,000 Long-term debt (a) 500,168 562,969 502,431 518,811 (a) Includes long-term debt due within one year. Excludes debt issuance costs and unamortized discount of $ 4.3 $ 4.5 b. Recurring Fair Value Measurements. The following table presents the balances of assets and liabilities measured at fair value on a recurring basis. Fair Value as of June 30, 2019 (In thousands) Total Level 1 Level 2 Level 3 MGE Energy Assets: Derivatives, net (b) $ 1,089 $ 342 $ - $ 747 Exchange-traded investments 1,079 1,079 - - Total Assets $ 2,168 $ 1,421 $ - $ 747 Liabilities: Derivatives, net $ 34,605 $ 521 $ - $ 34,084 Deferred compensation 3,131 - 3,131 - Total Liabilities $ 37,736 $ 521 $ 3,131 $ 34,084 MGE Assets: Derivatives, net (b) $ 1,089 $ 342 $ - $ 747 Exchange-traded investments 189 189 - - Total Assets $ 1,278 $ 531 $ - $ 747 Liabilities: Derivatives, net $ 34,605 $ 521 $ - $ 34,084 Deferred compensation 3,131 - 3,131 - Total Liabilities $ 37,736 $ 521 $ 3,131 $ 34,084 Fair Value as of December 31, 2018 (In thousands) Total Level 1 Level 2 Level 3 MGE Energy Assets: Derivatives, net $ 1,042 $ 296 $ - $ 746 Exchange-traded investments 848 848 - - Total Assets $ 1,890 $ 1,144 $ - $ 746 Liabilities: Derivatives, net $ 32,872 $ 124 $ - $ 32,748 Deferred compensation 3,078 - 3,078 - Total Liabilities $ 35,950 $ 124 $ 3,078 $ 32,748 MGE Assets: Derivatives, net $ 1,042 $ 296 $ - $ 746 Exchange-traded investments 43 43 - - Total Assets $ 1,085 $ 339 $ - $ 746 Liabilities: Derivatives, net $ 32,872 $ 124 $ - $ 32,748 Deferred compensation 3,078 - 3,078 - Total Liabilities $ 35,950 $ 124 $ 3,078 $ 32,748 (b) These amounts are shown gross and exclude $ 0 No transfers were made in or out of Level 1 or Level 2 for the six months ended June 30, 2019. Investments include exchange-traded investment securities valued using quoted prices on active exchanges and are therefore classified as Level 1. Derivatives include exchange-traded derivative contracts, over-the-counter transactions, a purchased power agreement, and FTRs. Most exchange-traded derivative contracts are valued based on unadjusted quoted prices in active markets and are therefore classified as Level 1. A small number of exchange-traded derivative contracts are valued using quoted market pricing in markets with insufficient volumes and are therefore considered unobservable and classified as Level 3. Transactions done with an over-the-counter party are on inactive markets and are therefore classified as Level 3. These transactions are valued based on quoted prices from markets with similar exchange-traded transactions. FTRs are priced based upon monthly auction results for identical or similar instruments in a closed market with limited data available and are therefore classified as Level 3. The purchased power agreement (see Footnote 11) was valued using an internally-developed pricing model and therefore is classified as Level 3. The model projects future market energy prices and compares those prices to the projected power costs to be incurred under the contract. Inputs to the model require significant management judgment and estimation. Future energy prices are based on a forward power pricing curve using exchange-traded contracts in the electric futures market. A basis adjustment is applied to the market energy price to reflect the price differential between the market price delivery point and the counterparty delivery point. The historical relationship between the delivery points is reviewed and a discount (below 100%) or premium (above 100%) is derived. This comparison is done for both peak times when demand is high and off-peak times when demand is low. If the basis adjustment is lowered, the fair value measurement will decrease, and if the basis adjustment is increased, the fair value measurement will increase. The projected power costs anticipated to be incurred under the purchased power agreement are determined using many factors, including historical generating costs, future prices, and expected fuel mix of the counterparty. An increase in the projected fuel costs would result in a decrease in the fair value measurement of the purchased power agreement. A significant input that MGE estimates is the counterparty's fuel mix in determining the projected power cost. MGE also considers the assumptions that market participants would use in valuing the asset or liability. This consideration includes assumptions about market risk such as liquidity, volatility, and contract duration. The fair value model uses a discount rate that incorporates discounting, credit, and model risks. The following table presents the significant unobservable inputs used in the pricing model. Model Input Significant Unobservable Inputs June 30, 2019 December 31, 2018 Basis adjustment: On peak 92.2% 92.1% Off peak 92.7% 92.8% Counterparty fuel mix: Internal generation 40.0% - 60.0% 50.0% - 75.0% Purchased power 60.0% - 40.0% 50.0% - 25.0% The deferred compensation plan allows participants to defer certain cash compensation into a notional investment account. These amounts are included within other deferred liabilities in the consolidated balance sheets. The notional investments earn interest based upon the semiannual rate of U.S. Treasury Bills having a 26 1% compounded monthly with a minimum annual rate of 7%, compounded monthly. The notional investments are based upon observable market data, however, since the deferred compensation obligations themselves are not exchanged in an active market, they are classified as Level 2. The following table summarizes the changes in Level 3 commodity derivative assets and liabilities measured at fair value on a recurring basis. Three Months Ended Six Months Ended June 30, June 30, (In thousands) 2019 2018 2019 2018 Beginning balance $ ( 31,283) $ ( 41,463) $ ( 32,002) $ ( 42,026) Realized and unrealized gains (losses): Included in regulatory assets ( 2,054) 4,130 ( 1,335) 4,693 Included in other comprehensive income - - - - Included in earnings ( 792) 82 ( 1,436) ( 460) Included in current assets ( 376) ( 297) ( 203) ( 470) Purchases 5,858 6,032 11,623 11,866 Sales - - - - Issuances - - - - Settlements ( 4,690) ( 5,816) ( 9,984) ( 10,935) Transfers in and/or out of Level 3 - - - - Balance as of June 30, $ ( 33,337) $ ( 37,332) $ ( 33,337) $ ( 37,332) Total gains (losses) included in earnings attributed to the change in unrealized gains (losses) related to assets and liabilities held at June 30, (c) $ - $ - $ - $ - The following table presents total realized and unrealized gains (losses) included in income for Level 3 assets and liabilities measured at fair value on a recurring basis (c) Three Months Ended Six Months Ended June 30, June 30, (In thousands) 2019 2018 2019 2018 Purchased Power Expense $ ( 693) $ 60 $ ( 1,249) $ ( 663) Cost of Gas Sold Expense ( 99) 22 ( 187) 203 Total $ (792) $ 82 $ (1,436) $ (460) (c) MGE's exchange-traded derivative contracts, over-the-counter party transactions, purchased power agreement, and FTRs are subject to regulatory deferral. These derivatives are therefore marked to fair value and are offset in the financial statements with a corresponding regulatory asset or liability.

Asset Retirement Obligation

Asset Retirement Obligation	6 Months Ended
	Jun. 30, 2019
Asset Retirement Obligation Disclosure [Abstract]
Asset Retirement Obligation	Asset Retirement Obligation - MGE Energy and MGE. A liability for the fair value of an asset retirement obligation (ARO) is recognized in the period in which it is incurred if it can be reasonably estimated. The offsetting associated asset retirement costs are capitalized as a long-lived asset and depreciated over the asset's useful life. As of June 30, 2019, MGE recorded an obligation of $ 1.5 million for the fair value of its legal liability for an ARO associated with the Saratoga Wind Farm. MGE has regulatory treatment and recognizes regulatory assets or liabilities for the timing differences between when we recover legal AROs in rates and when those costs would actually be recognized.

Joint Plant Ownership

Joint Plant Ownership	6 Months Ended
	Jun. 30, 2019
Regulated Operations [Abstract]
Joint Plant Ownership	Joint Plant Ownership - MGE Energy and MGE. a. Two Creeks. In May 2019, MGE acquired a 33% ownership interest in a 150 MW solar generation array in the Town of Two Creeks and the City of Two Rivers in Manitowoc and Kewanee Counties, Wisconsin. MGE’s sole principal asset will be the 33% undivided ownership interest in the solar generation facility, which is being constructed. The estimated share of capital costs for MGE’s ownership interest is approximately $ 65 million (excluding capitalized interest). As of June 30, 2019, $ 16.5 million (excluding capitalized interest) related to this project is reflected in " Construction work in progress " on the consolidated balance sheets. The project is anticipated to be completed by the end of 2020. b. Badger Hollow. In July 2019, MGE acquired a 33% ownership interest in a 150 MW solar generation array in southwestern Wisconsin in Iowa County, near the villages of Montfort and Cobb. MGE’s sole principal asset will be the 33% undivided ownership interest in the solar generation facility which is being constructed. The estimated share of capital costs for MGE’s ownership interest is approximately $ 65 million (excluding capitalized interest). As of June 30, 2019, $ 1.0 million (excluding capitalized interest) related to this project is reflected in " Construction work in progress " on the consolidated balance sheets. The project is anticipated to be completed by the end of 2020.

Revenue

Revenue	6 Months Ended
	Jun. 30, 2019
Revenue from Contract with Customer [Abstract]
Revenue from Contract with Customer	Revenue - MGE Energy and MGE. Revenues disaggregated by revenue source were as follows: Three Months Ended Six Months Ended (In thousands) June 30, June 30, Electric revenues 2019 2018 2019 2018 Residential $ 30,749 $ 32,217 $ 65,330 $ 65,476 Commercial 52,762 50,174 102,015 97,626 Industrial 3,322 4,630 6,253 7,525 Other-retail/municipal 8,946 8,527 17,185 16,814 Total retail 95,779 95,548 190,783 187,441 Sales to the market 790 2,795 2,751 4,829 Other revenues 294 724 745 1,188 Total electric revenues 96,863 99,067 194,279 193,458 Gas revenues Residential 16,000 15,620 56,317 52,171 Commercial/Industrial 7,883 8,206 36,008 33,158 Total retail 23,883 23,826 92,325 85,329 Gas transportation 1,094 1,053 2,630 2,189 Other revenues 93 101 215 227 Total gas revenues 25,070 24,980 95,170 87,745 Non-regulated energy revenues 214 215 267 691 Total Operating Revenue $ 122,147 $ 124,262 289,716 $ 281,894 Performance Obligations A performance obligation is a promise in a contract to transfer a distinct good or service to the customer and is the unit of account. A contract's transaction price is allocated to each distinct performance obligation and recognized as revenue when, or as, the performance obligation is satisfied. The majority of MGE Energy's and MGE's contracts have a single performance obligation. Retail Revenue (Residential, Commercial, Industrial, and Other Retail/Municipal) Retail revenue of electric and gas utility service represent MGE's core business activities. Tariffs are approved by the PSCW through a rate order and provide MGE's customers with the standard terms and conditions, including pricing terms. The performance obligation to deliver electricity or gas is satisfied over time as the customer simultaneously receives and consumes the commodities provided by MGE. MGE recognizes revenues as the commodity is delivered to customers. Meters are read on a systematic basis throughout the month based on established meter-reading schedules and the customer is subsequently billed for their services. At the end of the month, MGE accrues an estimate for the unbilled amount of commodities delivered to customers. The unbilled revenue estimate is based on daily system demand volumes, weather factors, estimated line losses, estimated customer usage by class, and applicable customer rates. Utility Cost Recovery Mechanisms MGE's tariff rates include a provision for fuel cost recovery. The PSCW allows Wisconsin utilities to defer electric fuel-related costs, less excess revenues, that fall outside a symmetrical cost tolerance band. Any over/under recovery of the actual costs in a given year is determined in the following year and is then reflected in future billings to electric retail customers. Over-collection of fuel-related costs that are outside the approved range will be recognized as a reduction of revenue. Under-collection of these costs will be recognized in "Purchased power" expense in the consolidated statements of income. The cumulative effects of these deferred amounts will be recorded in "Regulatory assets" or "Regulatory liabilities" on the consolidated balance sheets until they are reflected in future billings to customers. See Footnote 10.b. for further information. MGE received a PSCW order in January 2018 to defer the over-collection of income tax expense collected in customer rates during 2018 as a result of the Tax Cuts and Jobs Act (the Tax Act) reduction in the income tax rate to 21 percent. MGE has other cost recovery mechanisms. For example, any over-collection of the difference between actual costs incurred and the amount of costs collected from customers is recorded as a reduction of revenue in the period incurred. Sales to the Market Sales to the market include energy charges, capacity or demand charges, and ancillary charges represented by wholesale sales of electricity made to third parties who are not ultimate users of the electricity. Most of these sales are spot market transactions on the markets operated by MISO. Each transaction is considered a performance obligation and revenue is recognized in the period in which energy charges, capacity or demand charges, and ancillary services are sold into MISO. MGE reports, on a net basis, transactions on the MISO markets in which it buys and sells power within the same hour to meet electric energy delivery requirements. Transportation of Gas MGE has contracts under which MGE provides gas transportation services to customers who have elected to purchase gas from a third party and have the gas delivered via pipelines within MGE's service territory. Revenue is recognized as service is rendered or gas is delivered to customers. Tariffs are approved by the PSCW through a rate order and provide gas transportation customers with the standard terms and conditions, including pricing terms.

Segment Information

Segment Information	6 Months Ended
	Jun. 30, 2019
Segment Reporting [Abstract]
Segment Information	Segment Information - MGE Energy and MGE. MGE Energy operates in the following business segments: electric utility, gas utility, nonregulated energy, transmission investment, and all other. See the 2018 Annual Report on Form 10-K for additional discussion of each of these segments. The following tables show segment information for MGE Energy's operations for the indicated periods: (In thousands) MGE Energy Electric Gas Non-regulated Energy Transmission Investment All Others Consolidation/ Elimination Entries Consolidated Total Three Months Ended June 30, 2019 Operating revenues $ 96,863 $ 25,070 $ 214 $ - $ - $ - $ 122,147 Interdepartmental revenues 198 1,929 9,995 - - ( 12,122) - Total operating revenues 97,061 26,999 10,209 - - (12,122) 122,147 Depreciation and amortization ( 13,379) ( 2,843) ( 1,869) - - - ( 18,091) Other operating expenses ( 73,130) ( 22,931) ( 33) - ( 301) 12,122 ( 84,273) Operating income (loss) 10,552 1,225 8,307 - ( 301) - 19,783 Other income (deductions), net 1,788 1,170 - 2,267 ( 206) - 5,019 Interest (expense) income, net ( 3,826) ( 1,032) ( 1,275) - 384 - ( 5,749) Income (loss) before taxes 8,514 1,363 7,032 2,267 ( 123) - 19,053 Income tax (provision) benefit ( 638) ( 412) ( 1,916) ( 619) 80 - ( 3,505) Net income (loss) $ 7,876 $ 951 $ 5,116 $ 1,648 $ ( 43) $ - $ 15,548 Three Months Ended June 30, 2018 Operating revenues $ 99,067 $ 24,980 $ 215 $ - $ - $ - $ 124,262 Interdepartmental revenues ( 245) 3,493 9,847 - - ( 13,095) - Total operating revenues 98,822 28,473 10,062 - - (13,095) 124,262 Depreciation and amortization ( 9,575) ( 2,445) ( 1,852) - - - ( 13,872) Other operating expenses ( 74,535) ( 24,232) ( 34) ( 5) ( 448) 13,095 ( 86,159) Operating income (loss) 14,712 1,796 8,176 ( 5) ( 448) - 24,231 Other income, net 1,562 752 - 1,916 501 - 4,731 Interest (expense) income, net ( 2,952) ( 887) ( 1,334) - 390 - ( 4,783) Income before taxes 13,322 1,661 6,842 1,911 443 - 24,179 Income tax provision ( 2,986) ( 372) ( 1,864) ( 522) ( 84) - ( 5,828) Net income $ 10,336 $ 1,289 $ 4,978 $ 1,389 $ 359 $ - $ 18,351 Six Months Ended June 30, 2019 Operating revenues $ 194,279 $ 95,170 $ 267 $ - $ - $ - $ 289,716 Interdepartmental revenues 397 6,891 19,968 - - ( 27,256) - Total operating revenues 194,676 102,061 20,235 - - (27,256) 289,716 Depreciation and amortization ( 25,888) ( 5,603) ( 3,739) - - - ( 35,230) Other operating expenses ( 146,424) ( 84,369) ( 81) - ( 575) 27,256 ( 204,193) Operating income (loss) 22,364 12,089 16,415 - ( 575) - 50,293 Other income, net 3,441 1,724 - 4,436 269 - 9,870 Interest (expense) income, net ( 7,491) ( 2,072) ( 2,565) - 732 - ( 11,396) Income before taxes 18,314 11,741 13,850 4,436 426 - 48,767 Income tax provision ( 1,088) ( 3,031) ( 3,773) ( 1,210) ( 111) - ( 9,213) Net income $ 17,226 $ 8,710 $ 10,077 $ 3,226 $ 315 $ - $ 39,554 Six Months Ended June 30, 2018 Operating revenues $ 193,458 $ 87,745 $ 691 $ - $ - $ - $ 281,894 Interdepartmental revenues ( 214) 7,840 19,667 - - ( 27,293) - Total operating revenues 193,244 95,585 20,358 - - (27,293) 281,894 Depreciation and amortization ( 18,953) ( 4,840) ( 3,702) - - - ( 27,495) Other operating expenses ( 151,110) ( 79,427) ( 77) ( 8) ( 651) 27,293 ( 203,980) Operating income (loss) 23,181 11,318 16,579 ( 8) ( 651) - 50,419 Other income, net 3,292 1,518 - 4,288 552 - 9,650 Interest (expense) income, net ( 5,819) ( 1,726) ( 2,682) - 705 - ( 9,522) Income before taxes 20,654 11,110 13,897 4,280 606 - 50,547 Income tax provision ( 4,186) ( 2,830) ( 3,786) ( 1,170) ( 223) - ( 12,195) Net income $ 16,468 $ 8,280 $ 10,111 $ 3,110 $ 383 $ - $ 38,352 The following tables show segment information for MGE's operations for the indicated periods: (In thousands) MGE Electric Gas Non-regulated Energy Consolidation/ Elimination Entries Consolidated Total Three Months Ended June 30, 2019 Operating revenues $ 96,863 $ 25,070 $ 214 $ - $ 122,147 Interdepartmental revenues 198 1,929 9,995 ( 12,122) - Total operating revenues 97,061 26,999 10,209 (12,122) 122,147 Depreciation and amortization ( 13,379) ( 2,843) ( 1,869) - ( 18,091) Other operating expenses ( 73,130) ( 22,931) ( 33) 12,122 ( 83,972) Operating income 10,552 1,225 8,307 - 20,084 Other income, net 1,788 1,170 - - 2,958 Interest expense, net ( 3,826) ( 1,032) ( 1,275) - ( 6,133) Income before taxes 8,514 1,363 7,032 - 16,909 Income tax provision ( 638) ( 412) ( 1,916) - ( 2,966) Net income 7,876 951 5,116 - 13,943 Less: Net income attributable to noncontrolling interest, net of tax - - - ( 5,621) ( 5,621) Net income attributable to MGE $ 7,876 $ 951 $ 5,116 $ ( 5,621) $ 8,322 Three Months Ended June 30, 2018 Operating revenues $ 99,067 $ 24,980 $ 215 $ - $ 124,262 Interdepartmental revenues ( 245) 3,493 9,847 ( 13,095) - Total operating revenues 98,822 28,473 10,062 (13,095) 124,262 Depreciation and amortization ( 9,575) ( 2,445) ( 1,852) - ( 13,872) Other operating expenses ( 74,535) ( 24,232) ( 35) 13,095 ( 85,707) Operating income 14,712 1,796 8,175 - 24,683 Other income, net 1,561 753 - - 2,314 Interest expense, net ( 2,952) ( 887) ( 1,334) - ( 5,173) Income before taxes 13,321 1,662 6,841 - 21,824 Income tax provision ( 2,985) ( 373) ( 1,863) - ( 5,221) Net income 10,336 1,289 4,978 - 16,603 Less: Net income attributable to noncontrolling interest, net of tax - - - ( 5,505) ( 5,505) Net income attributable to MGE $ 10,336 $ 1,289 $ 4,978 $ ( 5,505) $ 11,098 Six Months Ended June 30, 2019 Operating revenues $ 194,279 $ 95,170 $ 267 $ - $ 289,716 Interdepartmental revenues 397 6,891 19,968 ( 27,256) - Total operating revenues 194,676 102,061 20,235 (27,256) 289,716 Depreciation and amortization ( 25,888) ( 5,603) ( 3,739) - ( 35,230) Other operating expenses ( 146,424) ( 84,369) ( 81) 27,256 ( 203,618) Operating income 22,364 12,089 16,415 - 50,868 Other income, net 3,441 1,724 - - 5,165 Interest expense, net ( 7,491) ( 2,072) ( 2,565) - ( 12,128) Income before taxes 18,314 11,741 13,850 - 43,905 Income tax provision ( 1,088) ( 3,031) ( 3,773) - ( 7,892) Net income 17,226 8,710 10,077 - 36,013 Less: Net income attributable to noncontrolling interest, net of tax - - - ( 11,111) ( 11,111) Net income attributable to MGE $ 17,226 $ 8,710 $ 10,077 $ ( 11,111) $ 24,902 Six Months Ended June 30, 2018 Operating revenues $ 193,458 $ 87,745 $ 691 $ - $ 281,894 Interdepartmental revenues ( 214) 7,840 19,667 ( 27,293) - Total operating revenues 193,244 95,585 20,358 (27,293) 281,894 Depreciation and amortization ( 18,953) ( 4,840) ( 3,702) - ( 27,495) Other operating expenses ( 151,110) ( 79,427) ( 78) 27,293 ( 203,322) Operating income 23,181 11,318 16,578 - 51,077 Other income, net 3,292 1,519 - - 4,811 Interest expense, net ( 5,819) ( 1,726) ( 2,682) - ( 10,227) Income before taxes 20,654 11,111 13,896 - 45,661 Income tax provision ( 4,186) ( 2,831) ( 3,785) - ( 10,802) Net income 16,468 8,280 10,111 - 34,859 Less: Net income attributable to noncontrolling interest, net of tax - - - ( 11,311) ( 11,311) Net income attributable to MGE $ 16,468 $ 8,280 $ 10,111 $ ( 11,311) $ 23,548 The following table shows segment information for assets and capital expenditures: Utility Consolidated (In thousands) MGE Energy Electric Gas Non-regulated Energy Transmission Investment All Others Consolidation/ Elimination Entries Total Assets: June 30, 2019 $ 1,250,755 $ 369,467 $ 261,707 $ 68,350 $ 453,604 $ ( 377,797) $ 2,026,086 December 31, 2018 1,193,083 377,005 265,301 66,366 465,661 ( 378,798) 1,988,618 Capital Expenditures: Six months ended June 30, 2019 $ 62,281 $ 15,028 $ 1,783 $ - $ - $ - $ 79,092 Year ended Dec. 31, 2018 176,399 30,497 5,301 - - - 212,197 Utility Consolidated (In thousands) MGE Electric Gas Non-regulated Energy Elimination Entries Total Assets: June 30, 2019 $ 1,250,755 $ 369,467 $ 261,657 $ ( 213) $ 1,881,666 December 31, 2018 1,193,083 377,005 265,251 ( 448) 1,834,891 Capital Expenditures: Six months ended June 30, 2019 $ 62,281 $ 15,028 $ 1,783 $ - $ 79,092 Year ended Dec. 31, 2018 176,399 30,497 5,301 - 212,197

Significant Accounting Policies

Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2019
Accounting Policies [Abstract]
Variable Interest Entities	MGE Power Elm Road and MGE Power West Campus own electric generating assets and lease those assets to MGE. Both entities are variable interest entities under applicable authoritative accounting guidance. MGE is considered the primary beneficiary of these entities as a result of contractual agreements. As a result, MGE has consolidated MGE Power Elm Road and MGE Power West Campus.
New Accounting Pronouncements Disclosure	New Accounting Standards - MGE Energy and MGE. Recently Adopted Leases. In February 2016, the FASB issued authoritative guidance within the codification's Leases topic that provides guidance on the classification, recognition, measurement, and disclosure of leases. The new leasing standard establishes that a lease conveys the right to control the use of identified property, plant, or equipment for a period of time in exchange for consideration. Under the new guidance, lessees are required to recognize all leases with terms greater than one year, including operating leases, on the balance sheet by recording a right-of-use asset and lease liability. Prior to the authoritative guidance, only capital leases were recognized on the balance sheet by lessees. The new accounting guidance, as applied by lessors, is materially consistent with current GAAP. In January 2018, the FASB issued authoritative guidance which provided an optional practical expedient to grandfather the accounting for existing and expired land easements not accounted for as a lease under the new authoritative guidance. MGE Energy and MGE adopted this practical expedient. The lease authoritative guidance became effective January 1, 2019. MGE Energy and MGE adopted the standard upon the effective date. In compliance with authorized transition guidance, MGE Energy and MGE began applying the new standard on January 1, 2019, but will continue to present periods prior to that date according to the previous authoritative standard. There was no material impact on the consolidated net income or cash flows. See Footnote 3 for further lease information.
Leases	As part of its regular operations, MGE enters into various contracts related to IT equipment, substations, cell towers, land, wind easements, and other property in use for operations. A contract is or contains a lease if the contract conveys the right to control the use of identified property, plant, or equipment for a period of time in exchange for consideration. Determination as to whether an arrangement is or contains a lease is completed at inception. Leases with an initial term of 12 months or less are not recorded on the consolidated balance sheets; lease expense for these leases are recognized on a straight-line basis over the lease term. Leases with initial terms in excess of 12 months are recorded as operating or financing leases on the consolidated balance sheets. Operating lease assets and operating lease liabilities are recognized based on the present value of the future minimum lease payments over the lease term at commencement date. For leases that do not provide an implicit rate, a collateralized incremental borrowing rate based on the information available at commencement date, including lease term, is used in determining the present value of future payments. The operating lease asset also includes any lease payments made and excludes lease incentives and initial direct costs incurred. Lease terms may include options to extend or terminate the lease when it is reasonably certain that the option will be exercised. Operating lease expense is recognized on a straight-line basis over the lease term. MGE has regulatory treatment and recognizes regulatory assets or liabilities for timing differences between when net lease costs are recorded and when costs are recognized. As of June 30, 2019, MGE has no significant leases not yet commenced that would create significant future rights and obligations.
Investments - ATC and ATC Holdco	MGE Transco and MGEE Transco have accounted for their investments in ATC and ATC Holdco, respectively, under the equity method of accounting.
Pension and Other Postretirement Benefit Plan Assets	MGE maintains qualified and nonqualified pension plans, health care, and life insurance benefits. Additionally, MGE has defined contribution 401(k) benefit plans. The components of net periodic benefit cost, other than the service cost component, are recorded in " Other income, net " on the consolidated statements of income. The service cost component is recorded in " Other operations and maintenance " on the consolidated statements of income. The service cost component of net periodic benefit cost is eligible for capitalization within the consolidated balance sheets. MGE has regulatory treatment and recognizes regulatory assets or liabilities for timing differences between when net periodic benefit costs are recovered and when costs are recognized.
Common Stock	MGE Energy sells shares of its common stock through its Stock Plan. Those shares may be newly issued shares or shares that MGE Energy has purchased in the open market for resale to participants in the Stock Plan. All sales under the Stock Plan are covered by a shelf registration statement that MGE Energy filed with the SEC.
Share-based Compensation	Under MGE Energy ' s Director Incentive Plan and its Performance Unit Plan, non-employee directors and eligible employees, respectively, may receive performance units that entitle the holder to receive a cash payment equal to the value of a designated number of shares of MGE Energy's common stock, plus dividend equivalent payments thereon, at the end of the performance period set in the award. In 2019, 5,175 units were granted under the Director Incentive Plan and are subject to a three 17,022 units were granted under the Performance Unit Plan and are subject to a five required by applicable accounting standards. Changes in fair value as well as the original grant are recognized as compensation cost. Since this amount is remeasured throughout the vesting period, the compensation cost is subject to variability. For nonretirement eligible employees under the Performance Unit Plan, stock-based compensation costs are accrued and recognized using the graded vesting method. Compensation cost for retirement eligible employees or employees that will become retirement eligible during the vesting schedule are recognized on an abridged horizon as retirement eligibility accelerates vesting.
Wisconsin Fuel Rules	Fuel rules require the PSCW and Wisconsin utilities to defer electric fuel-related costs that fall outside a symmetrical cost tolerance band around the amount approved for a utility in its annual fuel proceedings. Any over/under recovery of the actual costs is determined in the following year and is then reflected in future billings to electric retail customers. The fuel rules bandwidth is currently set at plus or minus 2%. Under fuel rules, MGE would defer costs, less any excess revenues, if its actual electric fuel costs exceeded 102% of the electric fuel costs allowed in its latest rate order. Excess revenues are defined as revenues in the year in question that provide MGE with a greater return on common equity than authorized by the PSCW in MGE's latest rate order. Conversely, MGE is required to defer the benefit of lower costs if actual electric fuel costs were less than 98% of the electric fuel costs allowed in that order. These costs will be subject to the PSCW's annual review of fuel costs completed in the year following the deferral.
Derivative Hedging	As part of its regular operations, MGE enters into contracts, including options, swaps, futures, forwards, and other contractual commitments, to manage its exposure to commodity prices. To the extent that these contracts are derivatives, MGE assesses whether or not the normal purchases or normal sales exclusion applies. For contracts to which this exclusion cannot be applied, the derivatives are recognized in the consolidated balance sheets at fair value. MGE's financial commodity derivative activities are conducted in accordance with its electric and gas risk management program, which is approved by the PSCW and limits the volume MGE can hedge with specific risk management strategies. The maximum length of time over which cash flows related to energy commodities can be hedged is four net loss or net gain position, respectively. The deferred gain or loss is recognized in earnings in the delivery month applicable to the instrument. Gains and losses related to hedges qualifying for regulatory treatment are recoverable in gas rates through the PGA or in electric rates as a component of the fuel rules mechanism.
Derivative Netting	All derivative instruments in this table are presented on a gross basis and are calculated prior to the netting of instruments with the same counterparty under a master netting agreement as well as the netting of collateral. For financial statement purposes, instruments are netted with the same counterparty under a master netting agreement as well as the netting of collateral.
Recurring Fair Value Measurements	Fair value is defined as the price that would be received to sell an asset or would be paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants at the measurement date. The accounting standard clarifies that fair value should be based on the assumptions market participants would use when pricing the asset or liability including assumptions about risk. The standard also establishes a three-level fair value hierarchy based upon the observability of the assumptions used and requires the use of observable market data when available. The levels are: Level 1 - Pricing inputs are quoted prices within active markets for identical assets or liabilities. Level 2 - Pricing inputs are quoted prices within active markets for similar assets or liabilities; quoted prices for identical or similar instruments in markets that are not active; and model-derived valuations that are correlated with or otherwise verifiable by observable market data. Level 3 - Pricing inputs are unobservable and reflect management's best estimate of what market participants would use in pricing the asset or liability. The carrying amount of cash, cash equivalents, and outstanding commercial paper approximates fair market value due to the short maturity of those investments and obligations. The estimated fair market value of long-term debt is based on quoted market prices for similar financial instruments. Since long-term debt is not traded in an active market, it is classified as Level 2. Investments include exchange-traded investment securities valued using quoted prices on active exchanges and are therefore classified as Level 1. Derivatives include exchange-traded derivative contracts, over-the-counter transactions, a purchased power agreement, and FTRs. Most exchange-traded derivative contracts are valued based on unadjusted quoted prices in active markets and are therefore classified as Level 1. A small number of exchange-traded derivative contracts are valued using quoted market pricing in markets with insufficient volumes and are therefore considered unobservable and classified as Level 3. Transactions done with an over-the-counter party are on inactive markets and are therefore classified as Level 3. These transactions are valued based on quoted prices from markets with similar exchange-traded transactions. FTRs are priced based upon monthly auction results for identical or similar instruments in a closed market with limited data available and are therefore classified as Level 3. The purchased power agreement (see Footnote 11) was valued using an internally-developed pricing model and therefore is classified as Level 3. The model projects future market energy prices and compares those prices to the projected power costs to be incurred under the contract. Inputs to the model require significant management judgment and estimation. Future energy prices are based on a forward power pricing curve using exchange-traded contracts in the electric futures market. A basis adjustment is applied to the market energy price to reflect the price differential between the market price delivery point and the counterparty delivery point. The historical relationship between the delivery points is reviewed and a discount (below 100%) or premium (above 100%) is derived. This comparison is done for both peak times when demand is high and off-peak times when demand is low. If the basis adjustment is lowered, the fair value measurement will decrease, and if the basis adjustment is increased, the fair value measurement will increase. The projected power costs anticipated to be incurred under the purchased power agreement are determined using many factors, including historical generating costs, future prices, and expected fuel mix of the counterparty. An increase in the projected fuel costs would result in a decrease in the fair value measurement of the purchased power agreement. A significant input that MGE estimates is the counterparty's fuel mix in determining the projected power cost. MGE also considers the assumptions that market participants would use in valuing the asset or liability. This consideration includes assumptions about market risk such as liquidity, volatility, and contract duration. The fair value model uses a discount rate that incorporates discounting, credit, and model risks. The following table presents the significant unobservable inputs used in the pricing model. Model Input Significant Unobservable Inputs June 30, 2019 December 31, 2018 Basis adjustment: On peak 92.2% 92.1% Off peak 92.7% 92.8% Counterparty fuel mix: Internal generation 40.0% - 60.0% 50.0% - 75.0% Purchased power 60.0% - 40.0% 50.0% - 25.0% The deferred compensation plan allows participants to defer certain cash compensation into a notional investment account. These amounts are included within other deferred liabilities in the consolidated balance sheets. The notional investments earn interest based upon the semiannual rate of U.S. Treasury Bills having a 26 1% compounded monthly with a minimum annual rate of 7%, compounded monthly. The notional investments are based upon observable market data, however, since the deferred compensation obligations themselves are not exchanged in an active market, they are classified as Level 2.
Asset Retirement Obligations	A liability for the fair value of an asset retirement obligation (ARO) is recognized in the period in which it is incurred if it can be reasonably estimated. The offsetting associated asset retirement costs are capitalized as a long-lived asset and depreciated over the asset's useful life.
Revenue Recognition	Performance Obligations A performance obligation is a promise in a contract to transfer a distinct good or service to the customer and is the unit of account. A contract's transaction price is allocated to each distinct performance obligation and recognized as revenue when, or as, the performance obligation is satisfied. The majority of MGE Energy's and MGE's contracts have a single performance obligation. Retail Revenue (Residential, Commercial, Industrial, and Other Retail/Municipal) Retail revenue of electric and gas utility service represent MGE's core business activities. Tariffs are approved by the PSCW through a rate order and provide MGE's customers with the standard terms and conditions, including pricing terms. The performance obligation to deliver electricity or gas is satisfied over time as the customer simultaneously receives and consumes the commodities provided by MGE. MGE recognizes revenues as the commodity is delivered to customers. Meters are read on a systematic basis throughout the month based on established meter-reading schedules and the customer is subsequently billed for their services. At the end of the month, MGE accrues an estimate for the unbilled amount of commodities delivered to customers. The unbilled revenue estimate is based on daily system demand volumes, weather factors, estimated line losses, estimated customer usage by class, and applicable customer rates. Utility Cost Recovery Mechanisms MGE's tariff rates include a provision for fuel cost recovery. The PSCW allows Wisconsin utilities to defer electric fuel-related costs, less excess revenues, that fall outside a symmetrical cost tolerance band. Any over/under recovery of the actual costs in a given year is determined in the following year and is then reflected in future billings to electric retail customers. Over-collection of fuel-related costs that are outside the approved range will be recognized as a reduction of revenue. Under-collection of these costs will be recognized in "Purchased power" expense in the consolidated statements of income. The cumulative effects of these deferred amounts will be recorded in "Regulatory assets" or "Regulatory liabilities" on the consolidated balance sheets until they are reflected in future billings to customers. See Footnote 10.b. for further information. MGE received a PSCW order in January 2018 to defer the over-collection of income tax expense collected in customer rates during 2018 as a result of the Tax Cuts and Jobs Act (the Tax Act) reduction in the income tax rate to 21 percent. MGE has other cost recovery mechanisms. For example, any over-collection of the difference between actual costs incurred and the amount of costs collected from customers is recorded as a reduction of revenue in the period incurred. Sales to the Market Sales to the market include energy charges, capacity or demand charges, and ancillary charges represented by wholesale sales of electricity made to third parties who are not ultimate users of the electricity. Most of these sales are spot market transactions on the markets operated by MISO. Each transaction is considered a performance obligation and revenue is recognized in the period in which energy charges, capacity or demand charges, and ancillary services are sold into MISO. MGE reports, on a net basis, transactions on the MISO markets in which it buys and sells power within the same hour to meet electric energy delivery requirements. Transportation of Gas MGE has contracts under which MGE provides gas transportation services to customers who have elected to purchase gas from a third party and have the gas delivered via pipelines within MGE's service territory. Revenue is recognized as service is rendered or gas is delivered to customers. Tariffs are approved by the PSCW through a rate order and provide gas transportation customers with the standard terms and conditions, including pricing terms.

Summary of Significant Accoun_2

Summary of Significant Accounting Principles (Tables)	6 Months Ended
	Jun. 30, 2019
Cash, Cash Equivalents, And Restricted Cash [Abstract]
Cash, Cash Equivalents, and Restricted Cash	The following table presents the components of total cash, cash equivalents, and restricted cash on the consolidated balance sheets. MGE Energy MGE June 30, December 31, June 30, December 31, (In thousands) 2019 2018 2019 2018 Cash and cash equivalents $ 69,913 $ 83,102 $ 6,383 $ 4,843 Restricted cash 605 634 605 634 Receivable - margin account 1,304 1,193 1,304 1,193 Cash, cash equivalents, and restricted cash $ 71,822 $ 84,929 $ 8,292 $ 6,670

Leases (Tables)

Leases (Tables)	6 Months Ended
	Jun. 30, 2019
Leases [Abstract]
Lease Cost	The following table shows lease expense for the three and six months ended June 30, 2019: (In thousands) Three Months Ended Six Months Ended Income Statement Location Finance lease expense: Amortization of leased assets $ 437 $ 870 Depreciation and amortization Interest on lease liabilities 200 398 Interest expense, net Operating lease expense 33 60 Other operations and maintenance Total lease expense $ 670 $ 1,328
Lease Balance Sheet	The following table shows the lease assets and liabilities on the consolidated balance sheet as of June 30, 2019: (In thousands) Balance Sheet Location Lease assets: Finance lease assets $ 16,700 Finance lease assets Operating lease assets 216 Other deferred assets and other Total lease assets $ 16,916 Lease liabilities: Finance lease liabilities - current $ 1,007 Other current liabilities Finance lease liabilities - long-term 17,720 Finance lease liabilities Operating lease liabilities - current 104 Other current liabilities Operating lease liabilities - long-term 144 Other deferred liabilities and other Total lease liabilities $ 18,975
Other Financial Information	The following table shows other financial lease information for the six months ended June 30, 2019: (In thousands) Cash paid for amounts included in the measurement of lease liabilities: Finance leases - Financing cash flows $ 643 Finance leases - Operating cash flows 398 Operating leases - Operating cash flows 71 Lease assets obtained in exchange for lease liabilities: Finance leases 12,081 Operating leases 125
Weighted Average And Discount Rate	The following table shows the weighted average remaining lease terms and discounts as of June 30, 2019: Weighted-average remaining lease terms (in years): Finance leases 38 Operating leases 6 Weighted-average discount rates: Finance leases 4.36 % Operating leases 3.97 %
Lessee Operating Lease Liability Maturity	The following table shows maturities of lease liabilities as of June 30, 2019: (In thousands) Finance Operating 2019 $ 876 $ 54 2020 1,644 113 2021 1,428 46 2022 1,309 13 2023 1,228 2 Thereafter 41,316 52 Subtotal 47,801 280 Less: Present value discount ( 29,074) ( 32) Lease Liability $ 18,727 $ 248
Lessee Finance Lease Liability Maturity	The following table shows maturities of lease liabilities as of June 30, 2019: (In thousands) Finance Operating 2019 $ 876 $ 54 2020 1,644 113 2021 1,428 46 2022 1,309 13 2023 1,228 2 Thereafter 41,316 52 Subtotal 47,801 280 Less: Present value discount ( 29,074) ( 32) Lease Liability $ 18,727 $ 248
Operating Leases, Future Minimum Rental Payments	Future minimum rental payments as of December 31, 2018, under agreements classified as operating leases with noncancelable terms in excess of one year are as follows: (In thousands) 2019 2020 2021 2022 2023 Thereafter Minimum lease payments $ 1,646 $ 1,371 $ 1,095 $ 989 $ 975 $ 22,707

Investment in ATC and ATC Hol_2

Investment in ATC and ATC Holdco (Tables)	6 Months Ended
	Jun. 30, 2019
Equity Method Investments and Joint Ventures [Abstract]
Equity Method Investments Financial Data	MGE Transco and MGEE Transco have accounted for their investments in ATC and ATC Holdco, respectively, under the equity method of accounting. Equity earnings from investments are recorded as " Other income " on the consolidated statements of income of MGE Energy. MGE Transco recorded the following: Three Months Ended Six Months Ended June 30, June 30, (In thousands) 2019 2018 2019 2018 Equity earnings from investment in ATC $ 2,297 $ 1,990 $ 4,515 $ 4,441 Dividends from ATC (a) 1,733 2,959 3,745 2,959 Capital contributions to ATC 1,065 1,065 1,243 1,775 (a) MGE Transco recorded a $ 2.3 million dividend receivable from ATC as of December 31, 2017. A cash dividend was received in January of the proceeding year. MGE Transco recorded a $ 1.4 million dividend receivable from ATC as of June 30, 2018. A cash dividend was received in July 2018. ATC ' s summarized financial data is as follows: Three Months Ended Six Months Ended June 30, June 30, (In thousands) 2019 2018 2019 2018 Operating revenues $ 182,212 $ 165,506 $ 359,927 $ 330,935 Operating expenses ( 93,573) ( 91,474) ( 183,960) ( 176,367) Other income, net 287 1,520 547 1,631 Interest expense, net ( 28,838) ( 26,895) ( 57,956) ( 54,657) Earnings before members' income taxes $ 60,088 $ 48,657 $ 118,558 $ 101,542

Taxes (Tables)

Taxes (Tables)	6 Months Ended
	Jun. 30, 2019
Income Tax Disclosure [Abstract]
Effective Tax Rate Reconciliation	The consolidated income tax provision differs from the amount computed by applying the statutory federal income tax rate to income before income taxes, as follows: MGE Energy MGE Three Months Ended June 30, 2019 2018 2019 2018 Statutory federal income tax rate 21.0% 21.0% 21.0% 21.0% State income taxes, net of federal benefit 6.3% 6.3% 6.2% 6.2% Amortized investment tax credits ( 0.1% ( 0.1% ( 0.1% ( 0.1% Credit for electricity from wind energy (a) ( 6.2% ( 0.4% ( 6.8% ( 0.4% AFUDC equity, net ( 0.2% ( 1.1% ( 0.2% ( 1.1% Amortization of utility excess deferred tax - tax reform (b) ( 2.4% ( 1.9% ( 2.6% ( 1.9% Other, net, individually insignificant -% 0.3% 0.1% 0.2% Effective income tax rate 18.4% 24.1% 17.6% 23.9% MGE Energy MGE Six Months Ended June 30, 2019 2018 2019 2018 Statutory federal income tax rate 21.0% 21.0% 21.0% 21.0% State income taxes, net of federal benefit 6.3% 6.3% 6.2% 6.2% Amortized investment tax credits ( 0.1% ( 0.1% ( 0.1% ( 0.1% Credit for electricity from wind energy (a) ( 6.1% ( 0.3% ( 6.7% ( 0.3% AFUDC equity, net ( 0.2% ( 0.9% ( 0.2% ( 1.0% Amortization of utility excess deferred tax - tax reform (b) ( 2.4% ( 1.9% ( 2.6% ( 2.1% Other, net, individually insignificant 0.4% -% 0.4% -% Effective income tax rate 18.9% 24.1% 18.0% 23.7% (a) Saratoga Wind Farm became operational in February 2019. (b) Included are impacts of the Tax Cuts and Jobs Act for the regulated utility for excess deferred taxes recognized using a normalization method of accounting. For the three and six months ended June 30, 2019 , MGE recognized $ 0.5 million and $ 1.1 million, respectively, compared to $ 0.4 million and $ 0.9 million for the comparable periods in 2018. The amount and timing of the cash impacts will depend on the period over which certain income tax benefits are provided to customers, determined by the PSCW.

Pension and Other Postretirem_2

Pension and Other Postretirement Plans (Tables)	6 Months Ended
	Jun. 30, 2019
Compensation and Retirement Disclosure [Abstract]
Schedule of Net Periodic Benefit Costs	The following table presents the components of net periodic benefit costs recognized. Three Months Ended Six Months Ended June 30, June 30, (In thousands) 2019 2018 2019 2018 Pension Benefits Components of net periodic benefit cost: Service cost $ 1,221 $ 1,404 $ 2,362 $ 2,861 Interest cost 3,742 3,222 7,194 6,430 Expected return on assets ( 5,922) ( 6,552) ( 11,469) ( 13,120) Amortization of: Prior service credit ( 31) ( 11) ( 59) ( 22) Actuarial loss 1,985 1,341 3,714 2,639 Net periodic benefit (credit) cost $ 995 $ ( 596) $ 1,742 $ ( 1,212) Postretirement Benefits Components of net periodic benefit cost: Service cost $ 334 $ 310 $ 553 $ 642 Interest cost 865 648 1,442 1,306 Expected return on assets ( 676) ( 814) ( 1,357) ( 1,616) Amortization of: Transition obligation 1 - 2 1 Prior service credit ( 662) ( 667) ( 1,330) ( 1,334) Actuarial loss 94 116 200 244 Net periodic benefit (credit) cost $ ( 44) $ ( 407) $ ( 490) $ ( 757)

Commitments and Contingencies (

Commitments and Contingencies (Tables)	6 Months Ended
	Jun. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Purchase Contracts, Fiscal Year Maturity Schedule	The following table shows future commitments related to purchase contracts as of June 30, 2019: (In thousands) 2019 2020 2021 2022 2023 Thereafter Natural gas Transportation and storage (a) 10,102 21,700 21,432 21,432 21,432 54,663 Supply (b) 8,822 10,280 - - - - Solar farms (c) 74 147 2,572 156 160 10,474 Other 92 928 929 97 99 1,079 $ 19,090 $ 33,055 $ 24,933 $ 21,685 $ 21,691 $ 66,216 (a) MGE's natural gas transportation and storage contracts require fixed monthly payments for firm supply pipeline transportation and storage capacity. The pricing components of the fixed monthly payments for the transportation and storage contracts are established by FERC but may be subject to change. (b) These commitments include market-based pricing. (c) In July 2019 MGE entered into additional commitments related to operations of the Badger Hollow Solar Farm. The total of these commitments by year are as follows: $ 0.5 million in 2019, $ 0.2 million in 2020, $ 0.5 million in 2021, $ 0.6 million in 2022, $ 0.6 million in 2023, and $ 22.0 million thereafter.

Derivative and Hedging Instru_2

Derivative and Hedging Instruments (Tables)	6 Months Ended
	Jun. 30, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Gross Notional Volume of Open Derivatives	The gross notional volume of open derivatives is as follows: June 30, 2019 December 31, 2018 Commodity derivative contracts 507,720 MWh 386,440 MWh Commodity derivative contracts 7,140,000 Dth 5,260,000 Dth FTRs 5,853 MW 2,252 MW PPA 1,750 MW 2,050 MW
Fair Value of Derivative Instruments on the Balance Sheet	The following table summarizes the fair value of the derivative instruments on the consolidated balance sheets. All derivative instruments in this table are presented on a gross basis and are calculated prior to the netting of instruments with the same counterparty under a master netting agreement as well as the netting of collateral. For financial statement purposes, instruments are netted with the same counterparty under a master netting agreement as well as the netting of collateral. As of June 30, 2019, and December 31, 2018, the receivable margin account balance of $1.3 million and $1.2 million, respectively, is shown net of any collateral posted against derivative positions. Derivative Derivative (In thousands) Assets Liabilities Balance Sheet Location June 30, 2019 Commodity derivative contracts $ 578 $ 1,322 Other current assets (a) Commodity derivative contracts 81 713 Other deferred charges (a) FTRs 430 - Other current assets PPA N/A 10,670 Derivative liability (current) PPA N/A 21,900 Derivative liability (long-term) December 31, 2018 Commodity derivative contracts $ 727 $ 270 Other current assets Commodity derivative contracts 74 72 Other deferred charges FTRs 241 - Other current assets PPA N/A 8,550 Derivative liability (current) PPA N/A 23,980 Derivative liability (long-term) (a) As of June 30, 2019, collateral of $0 million was posted against and netted with derivative liability positions on the consolidated balance sheets. No collateral was posted against derivative positions as of December 31, 2018.
Offsetting Assets	The following tables show the effect of netting arrangements for recognized derivative assets and liabilities that are subject to a master netting arrangement or similar arrangement on the consolidated balance sheets. Offsetting of Derivative Assets (In thousands) Gross Amounts Gross Amounts Offset in Balance Sheets Collateral Posted Against Derivative Positions Net Amount Presented in Balance Sheets June 30, 2019 Commodity derivative contracts $ 659 $ ( 343) $ - $ 316 FTRs 430 - - 430 December 31, 2018 Commodity derivative contracts $ 801 $ ( 342) $ - $ 459 FTRs 241 - - 241
Offsetting Liabilities	Offsetting of Derivative Liabilities (In thousands) Gross Amounts Gross Amounts Offset in Balance Sheets Collateral Posted Against Derivative Positions Net Amount Presented in Balance Sheets June 30, 2019 Commodity derivative contracts $ 2,035 $ ( 343) $ ( 1,692) $ - PPA 32,570 - - 32,570 December 31, 2018 Commodity derivative contracts $ 342 $ ( 342) $ - $ - PPA 32,530 - - 32,530
Derivative Gains and Losses in Balance Sheet	The following tables summarize the unrealized and realized gains (losses) related to the derivative instruments on the consolidated balance sheets and the consolidated statements of income. 2019 2018 (In thousands) Current and Long-Term Regulatory Asset Other Current Assets Current and Long-Term Regulatory Asset Other Current Assets Three Months Ended June 30: Balance at April 1, $ 31,023 $ 259 $ 41,241 $ 319 Unrealized gain 3,228 - ( 4,027) - Realized (loss) gain reclassified to a deferred account ( 731) 731 ( 363) 363 Realized (loss) gain reclassified to income statement ( 4) ( 112) 73 ( 42) Balance as of June 30, $ 33,516 $ 878 $ 36,924 $ 640 Six Months Ended June 30: Balance at January 1, $ 31,830 $ 377 $ 41,958 $ 806 Unrealized gain 2,306 - ( 3,899) - Realized (loss) gain reclassified to a deferred account ( 991) 991 ( 521) 521 Realized (loss) gain reclassified to income statement 371 ( 490) ( 614) ( 687) Balance as of June 30, $ 33,516 $ 878 $ 36,924 $ 640
Derivative Gains and Losses in Income Statement	Realized Losses (Gains) 2019 2018 (In thousands) Fuel for Electric Generation/ Purchased Power Cost of Gas Sold Fuel for Electric Generation/ Purchased Power Cost of Gas Sold Three Months Ended June 30: Commodity derivative contracts $ 299 $ 99 $ ( 190) $ 22 FTRs 61 - ( 300) - PPA ( 343) - 437 - Six Months Ended June 30: Commodity derivative contracts $ 568 $ 377 $ 184 $ 637 FTRs ( 74) - ( 475) - PPA ( 752) - 955 -

Fair Value of Financial Instr_2

Fair Value of Financial Instruments (Tables)	6 Months Ended
	Jun. 30, 2019
Fair Value Disclosures [Abstract]
Estimated Fair Market Value of Financial Instruments	The estimated fair market value of financial instruments are as follows: June 30, 2019 December 31, 2018 (In thousands) Carrying Amount Fair Value Carrying Amount Fair Value MGE Energy Assets: Cash and cash equivalents $ 69,913 $ 69,913 $ 83,102 $ 83,102 Liabilities: Short-term debt - commercial paper 23,500 23,500 13,000 13,000 Long-term debt (a) 500,168 562,969 502,431 518,811 MGE Assets: Cash and cash equivalents $ 6,383 $ 6,383 $ 4,843 $ 4,843 Liabilities: Short-term debt - commercial paper 23,500 23,500 13,000 13,000 Long-term debt (a) 500,168 562,969 502,431 518,811 (a) Includes long-term debt due within one year. Excludes debt issuance costs and unamortized discount of $ 4.3 $ 4.5
Assets and Liabilities Measured at Fair Value on a Recurring Basis	The following table presents the balances of assets and liabilities measured at fair value on a recurring basis. Fair Value as of June 30, 2019 (In thousands) Total Level 1 Level 2 Level 3 MGE Energy Assets: Derivatives, net (b) $ 1,089 $ 342 $ - $ 747 Exchange-traded investments 1,079 1,079 - - Total Assets $ 2,168 $ 1,421 $ - $ 747 Liabilities: Derivatives, net $ 34,605 $ 521 $ - $ 34,084 Deferred compensation 3,131 - 3,131 - Total Liabilities $ 37,736 $ 521 $ 3,131 $ 34,084 MGE Assets: Derivatives, net (b) $ 1,089 $ 342 $ - $ 747 Exchange-traded investments 189 189 - - Total Assets $ 1,278 $ 531 $ - $ 747 Liabilities: Derivatives, net $ 34,605 $ 521 $ - $ 34,084 Deferred compensation 3,131 - 3,131 - Total Liabilities $ 37,736 $ 521 $ 3,131 $ 34,084 Fair Value as of December 31, 2018 (In thousands) Total Level 1 Level 2 Level 3 MGE Energy Assets: Derivatives, net $ 1,042 $ 296 $ - $ 746 Exchange-traded investments 848 848 - - Total Assets $ 1,890 $ 1,144 $ - $ 746 Liabilities: Derivatives, net $ 32,872 $ 124 $ - $ 32,748 Deferred compensation 3,078 - 3,078 - Total Liabilities $ 35,950 $ 124 $ 3,078 $ 32,748 MGE Assets: Derivatives, net $ 1,042 $ 296 $ - $ 746 Exchange-traded investments 43 43 - - Total Assets $ 1,085 $ 339 $ - $ 746 Liabilities: Derivatives, net $ 32,872 $ 124 $ - $ 32,748 Deferred compensation 3,078 - 3,078 - Total Liabilities $ 35,950 $ 124 $ 3,078 $ 32,748 (b) These amounts are shown gross and exclude $ 0
Significant Unobservable Inputs	The following table presents the significant unobservable inputs used in the pricing model. Model Input Significant Unobservable Inputs June 30, 2019 December 31, 2018 Basis adjustment: On peak 92.2% 92.1% Off peak 92.7% 92.8% Counterparty fuel mix: Internal generation 40.0% - 60.0% 50.0% - 75.0% Purchased power 60.0% - 40.0% 50.0% - 25.0%
Changes in Level 3 Assets and Liabilities Measured at Fair Value on a Recurring Basis	The following table summarizes the changes in Level 3 commodity derivative assets and liabilities measured at fair value on a recurring basis. Three Months Ended Six Months Ended June 30, June 30, (In thousands) 2019 2018 2019 2018 Beginning balance $ ( 31,283) $ ( 41,463) $ ( 32,002) $ ( 42,026) Realized and unrealized gains (losses): Included in regulatory assets ( 2,054) 4,130 ( 1,335) 4,693 Included in other comprehensive income - - - - Included in earnings ( 792) 82 ( 1,436) ( 460) Included in current assets ( 376) ( 297) ( 203) ( 470) Purchases 5,858 6,032 11,623 11,866 Sales - - - - Issuances - - - - Settlements ( 4,690) ( 5,816) ( 9,984) ( 10,935) Transfers in and/or out of Level 3 - - - - Balance as of June 30, $ ( 33,337) $ ( 37,332) $ ( 33,337) $ ( 37,332) Total gains (losses) included in earnings attributed to the change in unrealized gains (losses) related to assets and liabilities held at June 30, (c) $ - $ - $ - $ - (c) MGE's exchange-traded derivative contracts, over-the-counter party transactions, purchased power agreement, and FTRs are subject to regulatory deferral. These derivatives are therefore marked to fair value and are offset in the financial statements with a corresponding regulatory asset or liability.
Gains and Losses Included in Income for Level 3 Assets and Liabilities Measured at Fair Value on a Recurring Basis	The following table presents total realized and unrealized gains (losses) included in income for Level 3 assets and liabilities measured at fair value on a recurring basis (c) Three Months Ended Six Months Ended June 30, June 30, (In thousands) 2019 2018 2019 2018 Purchased Power Expense $ ( 693) $ 60 $ ( 1,249) $ ( 663) Cost of Gas Sold Expense ( 99) 22 ( 187) 203 Total $ (792) $ 82 $ (1,436) $ (460) (c) MGE's exchange-traded derivative contracts, over-the-counter party transactions, purchased power agreement, and FTRs are subject to regulatory deferral. These derivatives are therefore marked to fair value and are offset in the financial statements with a corresponding regulatory asset or liability.

Revenue (Tables)

Revenue (Tables)	6 Months Ended
	Jun. 30, 2019
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue	Revenues disaggregated by revenue source were as follows: Three Months Ended Six Months Ended (In thousands) June 30, June 30, Electric revenues 2019 2018 2019 2018 Residential $ 30,749 $ 32,217 $ 65,330 $ 65,476 Commercial 52,762 50,174 102,015 97,626 Industrial 3,322 4,630 6,253 7,525 Other-retail/municipal 8,946 8,527 17,185 16,814 Total retail 95,779 95,548 190,783 187,441 Sales to the market 790 2,795 2,751 4,829 Other revenues 294 724 745 1,188 Total electric revenues 96,863 99,067 194,279 193,458 Gas revenues Residential 16,000 15,620 56,317 52,171 Commercial/Industrial 7,883 8,206 36,008 33,158 Total retail 23,883 23,826 92,325 85,329 Gas transportation 1,094 1,053 2,630 2,189 Other revenues 93 101 215 227 Total gas revenues 25,070 24,980 95,170 87,745 Non-regulated energy revenues 214 215 267 691 Total Operating Revenue $ 122,147 $ 124,262 289,716 $ 281,894

Segment Information (Tables)

Segment Information (Tables)	6 Months Ended
	Jun. 30, 2019
Segment Reporting [Abstract]
Segment Information	The following tables show segment information for MGE Energy's operations for the indicated periods: (In thousands) MGE Energy Electric Gas Non-regulated Energy Transmission Investment All Others Consolidation/ Elimination Entries Consolidated Total Three Months Ended June 30, 2019 Operating revenues $ 96,863 $ 25,070 $ 214 $ - $ - $ - $ 122,147 Interdepartmental revenues 198 1,929 9,995 - - ( 12,122) - Total operating revenues 97,061 26,999 10,209 - - (12,122) 122,147 Depreciation and amortization ( 13,379) ( 2,843) ( 1,869) - - - ( 18,091) Other operating expenses ( 73,130) ( 22,931) ( 33) - ( 301) 12,122 ( 84,273) Operating income (loss) 10,552 1,225 8,307 - ( 301) - 19,783 Other income (deductions), net 1,788 1,170 - 2,267 ( 206) - 5,019 Interest (expense) income, net ( 3,826) ( 1,032) ( 1,275) - 384 - ( 5,749) Income (loss) before taxes 8,514 1,363 7,032 2,267 ( 123) - 19,053 Income tax (provision) benefit ( 638) ( 412) ( 1,916) ( 619) 80 - ( 3,505) Net income (loss) $ 7,876 $ 951 $ 5,116 $ 1,648 $ ( 43) $ - $ 15,548 Three Months Ended June 30, 2018 Operating revenues $ 99,067 $ 24,980 $ 215 $ - $ - $ - $ 124,262 Interdepartmental revenues ( 245) 3,493 9,847 - - ( 13,095) - Total operating revenues 98,822 28,473 10,062 - - (13,095) 124,262 Depreciation and amortization ( 9,575) ( 2,445) ( 1,852) - - - ( 13,872) Other operating expenses ( 74,535) ( 24,232) ( 34) ( 5) ( 448) 13,095 ( 86,159) Operating income (loss) 14,712 1,796 8,176 ( 5) ( 448) - 24,231 Other income, net 1,562 752 - 1,916 501 - 4,731 Interest (expense) income, net ( 2,952) ( 887) ( 1,334) - 390 - ( 4,783) Income before taxes 13,322 1,661 6,842 1,911 443 - 24,179 Income tax provision ( 2,986) ( 372) ( 1,864) ( 522) ( 84) - ( 5,828) Net income $ 10,336 $ 1,289 $ 4,978 $ 1,389 $ 359 $ - $ 18,351 Six Months Ended June 30, 2019 Operating revenues $ 194,279 $ 95,170 $ 267 $ - $ - $ - $ 289,716 Interdepartmental revenues 397 6,891 19,968 - - ( 27,256) - Total operating revenues 194,676 102,061 20,235 - - (27,256) 289,716 Depreciation and amortization ( 25,888) ( 5,603) ( 3,739) - - - ( 35,230) Other operating expenses ( 146,424) ( 84,369) ( 81) - ( 575) 27,256 ( 204,193) Operating income (loss) 22,364 12,089 16,415 - ( 575) - 50,293 Other income, net 3,441 1,724 - 4,436 269 - 9,870 Interest (expense) income, net ( 7,491) ( 2,072) ( 2,565) - 732 - ( 11,396) Income before taxes 18,314 11,741 13,850 4,436 426 - 48,767 Income tax provision ( 1,088) ( 3,031) ( 3,773) ( 1,210) ( 111) - ( 9,213) Net income $ 17,226 $ 8,710 $ 10,077 $ 3,226 $ 315 $ - $ 39,554 Six Months Ended June 30, 2018 Operating revenues $ 193,458 $ 87,745 $ 691 $ - $ - $ - $ 281,894 Interdepartmental revenues ( 214) 7,840 19,667 - - ( 27,293) - Total operating revenues 193,244 95,585 20,358 - - (27,293) 281,894 Depreciation and amortization ( 18,953) ( 4,840) ( 3,702) - - - ( 27,495) Other operating expenses ( 151,110) ( 79,427) ( 77) ( 8) ( 651) 27,293 ( 203,980) Operating income (loss) 23,181 11,318 16,579 ( 8) ( 651) - 50,419 Other income, net 3,292 1,518 - 4,288 552 - 9,650 Interest (expense) income, net ( 5,819) ( 1,726) ( 2,682) - 705 - ( 9,522) Income before taxes 20,654 11,110 13,897 4,280 606 - 50,547 Income tax provision ( 4,186) ( 2,830) ( 3,786) ( 1,170) ( 223) - ( 12,195) Net income $ 16,468 $ 8,280 $ 10,111 $ 3,110 $ 383 $ - $ 38,352 The following tables show segment information for MGE's operations for the indicated periods: (In thousands) MGE Electric Gas Non-regulated Energy Consolidation/ Elimination Entries Consolidated Total Three Months Ended June 30, 2019 Operating revenues $ 96,863 $ 25,070 $ 214 $ - $ 122,147 Interdepartmental revenues 198 1,929 9,995 ( 12,122) - Total operating revenues 97,061 26,999 10,209 (12,122) 122,147 Depreciation and amortization ( 13,379) ( 2,843) ( 1,869) - ( 18,091) Other operating expenses ( 73,130) ( 22,931) ( 33) 12,122 ( 83,972) Operating income 10,552 1,225 8,307 - 20,084 Other income, net 1,788 1,170 - - 2,958 Interest expense, net ( 3,826) ( 1,032) ( 1,275) - ( 6,133) Income before taxes 8,514 1,363 7,032 - 16,909 Income tax provision ( 638) ( 412) ( 1,916) - ( 2,966) Net income 7,876 951 5,116 - 13,943 Less: Net income attributable to noncontrolling interest, net of tax - - - ( 5,621) ( 5,621) Net income attributable to MGE $ 7,876 $ 951 $ 5,116 $ ( 5,621) $ 8,322 Three Months Ended June 30, 2018 Operating revenues $ 99,067 $ 24,980 $ 215 $ - $ 124,262 Interdepartmental revenues ( 245) 3,493 9,847 ( 13,095) - Total operating revenues 98,822 28,473 10,062 (13,095) 124,262 Depreciation and amortization ( 9,575) ( 2,445) ( 1,852) - ( 13,872) Other operating expenses ( 74,535) ( 24,232) ( 35) 13,095 ( 85,707) Operating income 14,712 1,796 8,175 - 24,683 Other income, net 1,561 753 - - 2,314 Interest expense, net ( 2,952) ( 887) ( 1,334) - ( 5,173) Income before taxes 13,321 1,662 6,841 - 21,824 Income tax provision ( 2,985) ( 373) ( 1,863) - ( 5,221) Net income 10,336 1,289 4,978 - 16,603 Less: Net income attributable to noncontrolling interest, net of tax - - - ( 5,505) ( 5,505) Net income attributable to MGE $ 10,336 $ 1,289 $ 4,978 $ ( 5,505) $ 11,098 Six Months Ended June 30, 2019 Operating revenues $ 194,279 $ 95,170 $ 267 $ - $ 289,716 Interdepartmental revenues 397 6,891 19,968 ( 27,256) - Total operating revenues 194,676 102,061 20,235 (27,256) 289,716 Depreciation and amortization ( 25,888) ( 5,603) ( 3,739) - ( 35,230) Other operating expenses ( 146,424) ( 84,369) ( 81) 27,256 ( 203,618) Operating income 22,364 12,089 16,415 - 50,868 Other income, net 3,441 1,724 - - 5,165 Interest expense, net ( 7,491) ( 2,072) ( 2,565) - ( 12,128) Income before taxes 18,314 11,741 13,850 - 43,905 Income tax provision ( 1,088) ( 3,031) ( 3,773) - ( 7,892) Net income 17,226 8,710 10,077 - 36,013 Less: Net income attributable to noncontrolling interest, net of tax - - - ( 11,111) ( 11,111) Net income attributable to MGE $ 17,226 $ 8,710 $ 10,077 $ ( 11,111) $ 24,902 Six Months Ended June 30, 2018 Operating revenues $ 193,458 $ 87,745 $ 691 $ - $ 281,894 Interdepartmental revenues ( 214) 7,840 19,667 ( 27,293) - Total operating revenues 193,244 95,585 20,358 (27,293) 281,894 Depreciation and amortization ( 18,953) ( 4,840) ( 3,702) - ( 27,495) Other operating expenses ( 151,110) ( 79,427) ( 78) 27,293 ( 203,322) Operating income 23,181 11,318 16,578 - 51,077 Other income, net 3,292 1,519 - - 4,811 Interest expense, net ( 5,819) ( 1,726) ( 2,682) - ( 10,227) Income before taxes 20,654 11,111 13,896 - 45,661 Income tax provision ( 4,186) ( 2,831) ( 3,785) - ( 10,802) Net income 16,468 8,280 10,111 - 34,859 Less: Net income attributable to noncontrolling interest, net of tax - - - ( 11,311) ( 11,311) Net income attributable to MGE $ 16,468 $ 8,280 $ 10,111 $ ( 11,311) $ 23,548 The following table shows segment information for assets and capital expenditures: Utility Consolidated (In thousands) MGE Energy Electric Gas Non-regulated Energy Transmission Investment All Others Consolidation/ Elimination Entries Total Assets: June 30, 2019 $ 1,250,755 $ 369,467 $ 261,707 $ 68,350 $ 453,604 $ ( 377,797) $ 2,026,086 December 31, 2018 1,193,083 377,005 265,301 66,366 465,661 ( 378,798) 1,988,618 Capital Expenditures: Six months ended June 30, 2019 $ 62,281 $ 15,028 $ 1,783 $ - $ - $ - $ 79,092 Year ended Dec. 31, 2018 176,399 30,497 5,301 - - - 212,197 Utility Consolidated (In thousands) MGE Electric Gas Non-regulated Energy Elimination Entries Total Assets: June 30, 2019 $ 1,250,755 $ 369,467 $ 261,657 $ ( 213) $ 1,881,666 December 31, 2018 1,193,083 377,005 265,251 ( 448) 1,834,891 Capital Expenditures: Six months ended June 30, 2019 $ 62,281 $ 15,028 $ 1,783 $ - $ 79,092 Year ended Dec. 31, 2018 176,399 30,497 5,301 - 212,197

Summary of Significant Accoun_3

Summary of Significant Accounting Principles (Details-1) - USD ($)	Jun. 30, 2019	Dec. 31, 2018	Jun. 30, 2018	Dec. 31, 2017
Cash Cash Equivalents And Restricted Cash [Line Items]
Cash and cash equivalents	$ 69,913,000	$ 83,102,000
Restricted cash	605,000	634,000
Receivable - margin account	1,304,000	1,193,000
Cash, cash equivalents, and restricted cash	71,822,000	84,929,000	$ 100,267,000	$ 112,094,000
MGE [Member]
Cash Cash Equivalents And Restricted Cash [Line Items]
Cash and cash equivalents	6,383,000	4,843,000
Restricted cash	605,000	634,000
Receivable - margin account	1,304,000	1,193,000
Cash, cash equivalents, and restricted cash	$ 8,292,000	$ 6,670,000	$ 7,816,000	$ 10,093,000

Leases (Details-1)

Leases (Details-1) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019
Lease Cost [Abstract]
Amortization of leased assets, Depreciation and amortization	$ 437	$ 870
Interest on lease liabilities, Interest expense, net	200	398
Operating lease expense, Other operations and maintenance	33	60
Total lease expense	$ 670	$ 1,328

Leases (Details-2)

Leases (Details-2) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Lessee Disclosure [Abstract]
Finance lease assets, net, Finance lease assets	$ 16,700	$ 2,181
Operating lease assets, Other deferred assets and other	216
Total lease assets	16,916
Finance lease liabilities - current, Other current liabilities	1,007
Finance lease liabilities - long term, Finance lease liabilities	17,720	$ 1,771
Operating lease liabilities - current, Other current liabilities	104
Operating lease liabilities - long term, Other deferred liabilities and other	144
Total lease liabilities	$ 18,975

Leases (Details-3)

Leases (Details-3) $ in Thousands	6 Months Ended
	Jun. 30, 2019USD ($)
Lessee Disclosure [Abstract]
Finance leases - Financing cash flows	$ 643
Finance leases - Operating cash flows	398
Operating leases - operating cash flows	71
Lease assets obtained in exchange for lease liabilities - finance leases	12,081
Lease assets obtained in exchange for lease liabilities - operating leases	$ 125

Leases (Details-4)

Leases (Details-4)	Jun. 30, 2019
Lessee Disclosure [Abstract]
Weighted average remaining lease term (years) finance leases	38 years
Weighted average remaining lease term (years) operating leases	6 years
Weighted average disocunt rate finance leases	4.36%
Weighted average disocunt rate operating leases	3.97%

Leases (Details-5)

Leases (Details-5) $ in Thousands	Jun. 30, 2019USD ($)
Finance Lease Liabilities Payments Due [Abstract]
2019	$ 876
2020	1,644
2021	1,428
2022	1,309
2023	1,228
Thereafter	41,316
Undiscounted finance lease liability	47,801
Less: Present value discount	(29,074)
Finance lease liability	18,727
Operating Lease Liabilities Payments Due [Abstract]
2019	54
2020	113
2021	46
2022	13
2023	2
Thereafter	52
Undiscounted operating lease liability	280
Less: Present value discount	(32)
Operating lease liability	$ 248

Leases (Details-6)

Leases (Details-6) $ in Thousands	Dec. 31, 2018USD ($)
Operating Leases Future Minimum Payments Due [Abstract]
Minimum lease payments, 2019	$ 1,646
Minimum lease payments, 2020	1,371
Minimum lease payments, 2021	1,095
Minimum lease payments, 2022	989
Minimum lease payments, 2023	975
Minimum lease payments, Thereafter	$ 22,707

Investment in ATC and ATC Hol_3

Investment in ATC and ATC Holdco (Details-1) - USD ($) $ in Thousands	Jul. 31, 2019	Jun. 30, 2019	Jun. 30, 2018		Jun. 30, 2019	Jun. 30, 2018		Dec. 31, 2017
Schedule Of Equity Method Investments [Line Items]
Equity earnings from investment in ATC		$ 2,297	$ 1,990		$ 4,515	$ 4,441
Dividends from ATC		1,733	2,959		3,745	3,905
Capital contributions to investments		1,065	1,065		3,386	3,280
MGE Transco [Member] | ATC [Member]
Schedule Of Equity Method Investments [Line Items]
Equity earnings from investment in ATC		2,297	1,990		4,515	4,441
Dividends from ATC		1,733	2,959	[1]	3,745	2,959	[1]
Capital contributions to investments		$ 1,065	1,065		$ 1,243	1,775
Dividend receivable from ATC			$ 1,400			$ 1,400		$ 2,300
MGE Transco [Member] | ATC [Member] | Subsequent Event [Member]
Schedule Of Equity Method Investments [Line Items]
Capital contributions to investments	$ 900
[1]	MGE Transco recorded a $ 2.3 million dividend receivable from ATC as of December 31, 2017. A cash dividend was received in January of the proceeding year. MGE Transco recorded a $ 1.4 million dividend receivable from ATC as of June 30, 2018. A cash dividend was received in July 2018.

Investment in ATC and ATC Hol_4

Investment in ATC and ATC Holdco (Details-2) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
ATC [Member]
Schedule Of Equity Method Investments [Line Items]
Operating revenues	$ 182,212	$ 165,506	$ 359,927	$ 330,935
Operating expenses	(93,573)	(91,474)	(183,960)	(176,367)
Other income, net	287	1,520	547	1,631
Interest expense, net	(28,838)	(26,895)	(57,956)	(54,657)
Earnings before members' income taxes	60,088	48,657	118,558	101,542
ATC [Member]
Related Party Transaction [Line Items]
Related party expenses	7,600	$ 7,200	15,200	$ 14,400
Due from related parties	$ 600		$ 600		$ 100

Taxes (Details)

Taxes (Details) - USD ($)		3 Months Ended			6 Months Ended
		Jun. 30, 2019		Jun. 30, 2018	Jun. 30, 2019		Jun. 30, 2018
Reconciliation of tax provision to statutory federal income tax rate [Abstract]
Statutory federal income tax rate		21.00%		21.00%	21.00%		21.00%
State income taxes, net of federal benefit		6.30%		6.30%	6.30%		6.30%
Amortized investment tax credits		(0.10%)		(0.10%)	(0.10%)		(0.10%)
Credit for electricity from wind energy		(6.20%)	[1]	(0.40%)	(6.10%)	[1]	(0.30%)
AFUDC equity, net		(0.20%)		(1.10%)	(0.20%)		(0.90%)
Amortization of utility excess deferred tax - tax reform	[2]	(2.40%)		(1.90%)	(2.40%)		(1.90%)
Other, net, individually significant		0.00%		0.30%	0.40%		0.00%
Effective income tax rate		18.40%		24.10%	18.90%		24.10%
Excess Deferred Taxes, Tax Cuts And Jobs Act [Member]
Effects Of The Tax Cuts And Jobs Act [Abstract]
Excess deferred tax - Income statement effect		$ 500,000		$ 400,000	$ 1,100,000		$ 900,000
MGE [Member]
Reconciliation of tax provision to statutory federal income tax rate [Abstract]
Statutory federal income tax rate		21.00%		21.00%	21.00%		21.00%
State income taxes, net of federal benefit		6.20%		6.20%	6.20%		6.20%
Amortized investment tax credits		(0.10%)		(0.10%)	(0.10%)		(0.10%)
Credit for electricity from wind energy		(6.80%)	[1]	(0.40%)	(6.70%)	[1]	(0.30%)
AFUDC equity, net		(0.20%)		(1.10%)	(0.20%)		(1.00%)
Amortization of utility excess deferred tax - tax reform	[2]	(2.60%)		(1.90%)	(2.60%)		(2.10%)
Other, net, individually significant		0.10%		0.20%	0.40%		0.00%
Effective income tax rate		17.60%		23.90%	18.00%		23.70%
[1]	Saratoga Wind Farm became operational in February 2019.
[2]	Included are impacts of the Tax Cuts and Jobs Act for the regulated utility for excess deferred taxes recognized using a normalization method of accounting. For the three and six months ended June 30, 2019 , MGE recognized $ 0.5 million and $ 1.1 million, respectively, compared to $ 0.4 million and $ 0.9 million for the comparable periods in 2018. The amount and timing of the cash impacts will depend on the period over which certain income tax benefits are provided to customers, determined by the PSCW.

Pension and Other Postretirem_3

Pension and Other Postretirement Plans (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Defined Benefit Plan Deferred Net Periodic Benefit Cost [Abstract]
Deferred pension and OPRB costs	$ 3,000		$ 3,000
Maximum PSCW approved deferred pension and OPRB costs			5,900
Pension Benefits [Member]
Components of net periodic benefit cost:
Service cost	1,221	$ 1,404	2,362	$ 2,861
Interest cost	3,742	3,222	7,194	6,430
Expected return on assets	(5,922)	(6,552)	(11,469)	(13,120)
Amortization of:
Prior service credit	(31)	(11)	(59)	(22)
Actuarial loss	1,985	1,341	3,714	2,639
Net periodic benefit (credit) cost	995	(596)	1,742	(1,212)
Postretirement Benefits [Member]
Components of net periodic benefit cost:
Service cost	334	310	553	642
Interest cost	865	648	1,442	1,306
Expected return on assets	(676)	(814)	(1,357)	(1,616)
Amortization of:
Transition obligation	1	0	2	1
Prior service credit	(662)	(667)	(1,330)	(1,334)
Actuarial loss	94	116	200	244
Net periodic benefit (credit) cost	$ (44)	$ (407)	$ (490)	$ (757)

Equity and Financing Arrangem_2

Equity and Financing Arrangements (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Common Stock [Abstract]
Common stock issued during period	0	0	0	0
Dilutive Shares Calculation [Abstract]
Dilutive securities			$ 0

Share Based Compensation (Detai

Share Based Compensation (Details) - Performance Units [Member] - USD ($)	1 Months Ended	3 Months Ended		6 Months Ended
	Jan. 31, 2019	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense		$ 700,000	$ 800,000	$ 1,900,000	$ 1,000,000
Cash payments distributed related to awards previously granted and now payable	$ 1,500,000
Awards forfeited during period, value		$ 0	$ 0	$ 0	$ 0
Awards forfeited during period, units		0	0	0	0
Outstanding awards vested during period				$ 5,700,000
Director Incentive Agreement [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards granted during period (in units)				5,175
Award vesting period				3 years
Performance Unit Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards granted during period (in units)				17,022
Award vesting period				5 years

Commitments and Contingencies_2

Commitments and Contingencies (Details-1)	Jun. 30, 2019MW
Minimum [Member]
EPA Greenhouse Gas Reduction Guidelines
Standard of Performance Plan For EGUs Over Threshold	25

Commitments and Contingencies_3

Commitments and Contingencies (Details-2) - USD ($)		Jul. 31, 2019	Jun. 30, 2019
Operating expense purchase contracts [Abstract]
Purchase obligation, 2019			$ 19,090,000
Purchase obligation, 2020			33,055,000
Purchase obligation, 2021			24,933,000
Purchase obligation, 2022			21,685,000
Purchase obligation, 2023			21,691,000
Purchase obligation, Thereafter			66,216,000
Natural Gas, Transportation and Storage [Member]
Operating expense purchase contracts [Abstract]
Purchase obligation, 2019	[1]		10,102,000
Purchase obligation, 2020	[1]		21,700,000
Purchase obligation, 2021	[1]		21,432,000
Purchase obligation, 2022	[1]		21,432,000
Purchase obligation, 2023	[1]		21,432,000
Purchase obligation, Thereafter	[1]		54,663,000
Natual Gas, Supply [Member]
Operating expense purchase contracts [Abstract]
Purchase obligation, 2019	[2]		8,822,000
Purchase obligation, 2020	[2]		10,280,000
Purchase obligation, 2021	[2]		0
Purchase obligation, 2022	[2]		0
Purchase obligation, 2023	[2]		0
Purchase obligation, Thereafter	[2]		0
Solar farms
Operating expense purchase contracts [Abstract]
Purchase obligation, 2019	[3]		74,000
Purchase obligation, 2020	[3]		147,000
Purchase obligation, 2021	[3]		2,572,000
Purchase obligation, 2022	[3]		156,000
Purchase obligation, 2023	[3]		160,000
Purchase obligation, Thereafter	[3]		10,474,000
Badger Hollow Additional Commitments [Member] | Subsequent Event [Member]
Operating expense purchase contracts [Abstract]
Purchase obligation, 2019	[3]	$ 500,000
Purchase obligation, 2020	[3]	200,000
Purchase obligation, 2021	[3]	500,000
Purchase obligation, 2022	[3]	600,000
Purchase obligation, 2023	[3]	600,000
Purchase obligation, Thereafter	[3]	22,000,000
Other [Member]
Operating expense purchase contracts [Abstract]
Purchase obligation, 2019			92,000
Purchase obligation, 2020			928,000
Purchase obligation, 2021			929,000
Purchase obligation, 2022			97,000
Purchase obligation, 2023			99,000
Purchase obligation, Thereafter			1,079,000
Two Creeks Construction Commitment [Member]
Long Term Purchase Commitment [Line Items]
Minimum future capital commitments			$ 52,800,000
Badger Hollow Construction Commitment [Member] | Subsequent Event [Member]
Long Term Purchase Commitment [Line Items]
Minimum future capital commitments		$ 59,900,000
[1]	MGE's natural gas transportation and storage contracts require fixed monthly payments for firm supply pipeline transportation and storage capacity. The pricing components of the fixed monthly payments for the transportation and storage contracts are established by FERC but may be subject to change.
[2]	These commitments include market-based pricing.
[3]	In July 2019 MGE entered into additional commitments related to operations of the Badger Hollow Solar Farm. The total of these commitments by year are as follows: $ 0.5 million in 2019, $ 0.2 million in 2020, $ 0.5 million in 2021, $ 0.6 million in 2022, $ 0.6 million in 2023, and $ 22.0 million thereafter.

Rate Matters (Details)

Rate Matters (Details) - PSCW [Member] - MGE [Member] - USD ($)	6 Months Ended	12 Months Ended
	Jun. 30, 2019	Dec. 31, 2020	Dec. 31, 2018	Jul. 31, 2019
Rate Proceedings [Abstract]
Authorized return on equity, percentage	9.80%	9.80%
Approved equity capital structure, percentage	56.60%	56.10%
Fuel Rules [Abstract]
Fuel rules, bandwidth	2.00%
Fuel rules, electric fuel deferred costs upper threshold	102.00%
Fuel rules, electric fuel deferred costs lower threshold	98.00%
Deferred fuel rules monitored costs	$ 0		$ 9,500,000
Public Utilities Fuel Surcharge Amount			$ 500,000
Public Utilities Fuel Surcharge Percentage			0.13%
Fuel Rules Refund, 2018 [Member] | Subsequent Event [Member]
Fuel Rules [Abstract]
Electric fuel credit ($)				$ 9,500,000
Electric Rate Proceeding [Member]
Rate Proceedings [Abstract]
Authorized rate increase (decrease), percentage	(2.24%)	0.00%
Authorized rate increase (decrease), amount	$ (9,200,000)
Gas Rate Proceeding [Member]
Rate Proceedings [Abstract]
Authorized rate increase (decrease), percentage	1.06%	1.46%
Authorized rate increase (decrease), amount	$ 1,700,000	$ 2,400,000

Derivative and Hedging Instru_3

Derivative and Hedging Instruments (Details-1) $ in Thousands	6 Months Ended		12 Months Ended
	Jun. 30, 2019USD ($)DthMWhMW		Dec. 31, 2018USD ($)DthMWhMW	Mar. 31, 2019USD ($)	Jun. 30, 2018USD ($)	Mar. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Derivative fair values [Abstract]
Receivable, margin account balance, net of collateral posted against derivative positions	$ 1,304		$ 1,193
Other Current Assets [Member]
Derivative fair values [Abstract]
Derivative fair value, net	878		377	$ 259	$ 640	$ 319	$ 806
Commodity Contracts And Financial Transimission Rights [Member]
Derivative fair values [Abstract]
Derivative fair value, net	$ (900)		$ 700
Commodity Derivative Contracts [Member]
Gross Notional Volume of Open Derivatives
Notional amount, energy measure (in MWh) | MWh	507,720		386,440
Notional amount, decatherm measure (in Dth) | Dth	7,140,000		5,260,000
Derivative fair values [Abstract]
Asset Derivatives, fair value, gross basis	$ 659		$ 801
Liability Derivatives, fair value, gross basis	2,035		342
Collateral posted against derivative positions	0		0
Commodity Derivative Contracts [Member] | Other Current Assets [Member]
Derivative fair values [Abstract]
Asset Derivatives, fair value, gross basis	578		727
Liability Derivatives, fair value, gross basis	1,322	[1]	270
Commodity Derivative Contracts [Member] | Other Deferred Charges [Member]
Derivative fair values [Abstract]
Asset Derivatives, fair value, gross basis	81		74
Liability Derivatives, fair value, gross basis	$ 713	[1]	$ 72
Energy Related Commodity Contract [Member] | Cash Flow Hedging [Member]
Derivatives Fair Value [Line Items]
Maximum term of derivative hedging contract	4 years
Financial Transmission Rights [Member]
Gross Notional Volume of Open Derivatives
Notional amount, power measure (in MW) | MW	5,853		2,252
Derivative fair values [Abstract]
Asset Derivatives, fair value, gross basis	$ 430		$ 241
Collateral posted against derivative positions	0		0
Financial Transmission Rights [Member] | Other Current Assets [Member]
Derivative fair values [Abstract]
Asset Derivatives, fair value, gross basis	430		241
Liability Derivatives, fair value, gross basis	$ 0		$ 0
PPA [Member]
Gross Notional Volume of Open Derivatives
Notional amount, power measure (in MW) | MW	1,750		2,050
Derivative fair values [Abstract]
Derivative fair value, net	$ (32,600)		$ (32,500)
Liability Derivatives, fair value, gross basis	32,570		32,530
PPA [Member] | Derivative Liability (Current) [Member]
Derivative fair values [Abstract]
Liability Derivatives, fair value, gross basis	10,670		8,550
PPA [Member] | Derivative Liability (Long-term) [Member]
Derivative fair values [Abstract]
Liability Derivatives, fair value, gross basis	$ 21,900		$ 23,980
[1]	As of June 30, 2019, collateral of $0 million was posted against and netted with derivative liability positions on the consolidated balance sheets. No collateral was posted against derivative positions as of December 31, 2018.

Derivative and Hedging Instru_4

Derivative and Hedging Instruments (Details-2) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Commodity Derivative Contracts [Member]
Offsetting Assets [Line Items]
Gross amounts	$ 659	$ 801
Gross amounts offset in balance sheet	(343)	(342)
Collateral posted against derivative positions	0	0
Net amount presented in balance sheet	316	459
Financial Transmission Rights [Member]
Offsetting Assets [Line Items]
Gross amounts	430	241
Gross amounts offset in balance sheet	0	0
Collateral posted against derivative positions	0	0
Net amount presented in balance sheet	$ 430	$ 241

Derivative and Hedging Instru_5

Derivative and Hedging Instruments (Details-3) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Commodity Derivative Contracts [Member]
Offsetting Liabilities [Line Items]
Gross amounts	$ 2,035	$ 342
Gross amounts offset in balance sheet	(343)	(342)
Collateral posted against derivative positions	(1,692)	0
Net amount presented in balance sheet	0	0
Purchased Power Agreement [Member]
Offsetting Liabilities [Line Items]
Gross amounts	32,570	32,530
Gross amounts offset in balance sheet	0	0
Collateral posted against derivative positions	0	0
Net amount presented in balance sheet	$ 32,570	$ 32,530

Derivative and Hedging Instru_6

Derivative and Hedging Instruments (Details-4) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Current and Long-Term Regulatory Asset [Member]
Change In Derivative Fair Value [Roll Forward]
Beginning balance,	$ 31,023	$ 41,241	$ 31,830	$ 41,958
Unrealized loss (gain)	3,228	(4,027)	2,306	(3,899)
Realized (loss) gain reclassified to a deferred account	(731)	(363)	(991)	(521)
Realized gain (loss) reclassified to income statement	(4)	73	371	(614)
Ending balance,	33,516	36,924	33,516	36,924
Other Current Assets [Member]
Change In Derivative Fair Value [Roll Forward]
Beginning balance,	259	319	377	806
Unrealized loss (gain)	0	0	0	0
Realized (loss) gain reclassified to a deferred account	731	363	991	521
Realized gain (loss) reclassified to income statement	(112)	(42)	(490)	(687)
Ending balance,	$ 878	$ 640	$ 878	$ 640

Derivative and Hedging Instru_7

Derivative and Hedging Instruments (Details-5)	3 Months Ended		6 Months Ended
	Jun. 30, 2019USD ($)counterparty	Jun. 30, 2018USD ($)	Jun. 30, 2019USD ($)counterparty	Jun. 30, 2018USD ($)	Dec. 31, 2018USD ($)
Counterparties in net liability position or default [Abstract]
Derivative, net liability position of counterparties	$ 0		$ 0		$ 0
Number of counterparties in default | counterparty	0		0
Commodity Derivative Contracts [Member] | Fuel For Electric Generation Purchased Power [Member]
Realized losses (gains) on income statement [Line Items]
Realized losses (gains) on income statement	$ 299,000	$ (190,000)	$ 568,000	$ 184,000
Commodity Derivative Contracts [Member] | Cost Of Gas Sold Expense [Member]
Realized losses (gains) on income statement [Line Items]
Realized losses (gains) on income statement	99,000	22,000	377,000	637,000
Financial Transmission Rights [Member] | Fuel For Electric Generation Purchased Power [Member]
Realized losses (gains) on income statement [Line Items]
Realized losses (gains) on income statement	61,000	(300,000)	(74,000)	(475,000)
Financial Transmission Rights [Member] | Cost Of Gas Sold Expense [Member]
Realized losses (gains) on income statement [Line Items]
Realized losses (gains) on income statement	0	0	0	0
Purchased Power Agreement [Member]
Derivative collateral required to be posted for PPA [Abstract]
Minimum collateral that may be required to be posted	20,000,000		20,000,000
Maximum collateral that may be required to be posted	40,000,000		40,000,000
Collateral posted	0		0
Purchased Power Agreement [Member] | Fuel For Electric Generation Purchased Power [Member]
Realized losses (gains) on income statement [Line Items]
Realized losses (gains) on income statement	(343,000)	437,000	(752,000)	955,000
Purchased Power Agreement [Member] | Cost Of Gas Sold Expense [Member]
Realized losses (gains) on income statement [Line Items]
Realized losses (gains) on income statement	$ 0	$ 0	$ 0	$ 0

Fair Value of Financial Instr_3

Fair Value of Financial Instruments (Details-1) - USD ($) $ in Thousands		Jun. 30, 2019	Dec. 31, 2018
Fair Value Measurement [Domain]
Liabilities:
Unamortized discount and debt issuance costs, net		$ 4,300	$ 4,500
Carrying Amount [Member]
Assets:
Cash and cash equivalents		69,913	83,102
Liabilities:
Short-term debt - commercial paper		23,500	13,000
Long-term debt	[1]	500,168	502,431
Fair Value [Member]
Assets:
Cash and cash equivalents		69,913	83,102
Liabilities:
Short-term debt - commercial paper		23,500	13,000
Long-term debt	[1]	562,969	518,811
MGE [Member] | Fair Value Measurement [Domain]
Liabilities:
Unamortized discount and debt issuance costs, net		4,300	4,500
MGE [Member] | Carrying Amount [Member]
Assets:
Cash and cash equivalents		6,383	4,843
Liabilities:
Short-term debt - commercial paper		23,500	13,000
Long-term debt	[1]	500,168	502,431
MGE [Member] | Fair Value [Member]
Assets:
Cash and cash equivalents		6,383	4,843
Liabilities:
Short-term debt - commercial paper		23,500	13,000
Long-term debt	[1]	$ 562,969	$ 518,811
[1]	Includes long-term debt due within one year. Excludes debt issuance costs and unamortized discount of $ 4.3 $ 4.5

Fair Value of Financial Instr_4

Fair Value of Financial Instruments (Details-2) - USD ($) $ in Thousands	Jun. 30, 2019		Dec. 31, 2018
Recurring [Member]
Assets:
Derivatives	$ 1,089	[1]	$ 1,042
Total Assets	2,168		1,890
Liabilities:
Derivatives	34,605		32,872
Deferred compensation	3,131		3,078
Total liabilities	37,736		35,950
Recurring [Member] | Exchange Traded [Member]
Assets:
Available-for-sale securities	1,079		848
Recurring [Member] | Level 1 [Member]
Assets:
Derivatives	342	[1]	296
Total Assets	1,421		1,144
Liabilities:
Derivatives	521		124
Deferred compensation	0		0
Total liabilities	521		124
Recurring [Member] | Level 1 [Member] | Exchange Traded [Member]
Assets:
Available-for-sale securities	1,079		848
Recurring [Member] | Level 2 [Member]
Assets:
Derivatives	0	[1]	0
Total Assets	0		0
Liabilities:
Derivatives	0		0
Deferred compensation	3,131		3,078
Total liabilities	3,131		3,078
Recurring [Member] | Level 2 [Member] | Exchange Traded [Member]
Assets:
Available-for-sale securities	0		0
Recurring [Member] | Level 3 [Member]
Assets:
Derivatives	747	[1]	746
Total Assets	747		746
Liabilities:
Derivatives	34,084		32,748
Deferred compensation	0		0
Total liabilities	34,084		32,748
Recurring [Member] | Level 3 [Member] | Exchange Traded [Member]
Assets:
Available-for-sale securities	0		0
MGE [Member]
Liabilities:
Collateral posted against derivative positions	1,700
MGE [Member] | Recurring [Member]
Assets:
Derivatives	1,089	[1]	1,042
Total Assets	1,278		1,085
Liabilities:
Derivatives	34,605		32,872
Deferred compensation	3,131		3,078
Total liabilities	37,736		35,950
MGE [Member] | Recurring [Member] | Exchange Traded [Member]
Assets:
Available-for-sale securities	189		43
MGE [Member] | Recurring [Member] | Level 1 [Member]
Assets:
Derivatives	342	[1]	296
Total Assets	531		339
Liabilities:
Derivatives	521		124
Deferred compensation	0		0
Total liabilities	521		124
MGE [Member] | Recurring [Member] | Level 1 [Member] | Exchange Traded [Member]
Assets:
Available-for-sale securities	189		43
MGE [Member] | Recurring [Member] | Level 2 [Member]
Assets:
Derivatives	0	[1]	0
Total Assets	0		0
Liabilities:
Derivatives	0		0
Deferred compensation	3,131		3,078
Total liabilities	3,131		3,078
MGE [Member] | Recurring [Member] | Level 2 [Member] | Exchange Traded [Member]
Assets:
Available-for-sale securities	0		0
MGE [Member] | Recurring [Member] | Level 3 [Member]
Assets:
Derivatives	747	[1]	746
Total Assets	747		746
Liabilities:
Derivatives	34,084		32,748
Deferred compensation	0		0
Total liabilities	34,084		32,748
MGE [Member] | Recurring [Member] | Level 3 [Member] | Exchange Traded [Member]
Assets:
Available-for-sale securities	$ 0		$ 0
[1]	These amounts are shown gross and exclude $ 0

Fair Value of Financial Instr_5

Fair Value of Financial Instruments (Details-3)	6 Months Ended	12 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Basis adjustment:
Basis adjustment - on peak	92.20%	92.10%
Basis adjustment - off peak	92.70%	92.80%
US Treasury Bill Securities [Member]
Deferred compensation plan [Abstract]
Investment interest calculation, investment maturity period (26 weeks)	182 days
Investment interest calculation, monthly compounding rate	1.00%
Investment interest calculation, minimum annual rate compounded monthly	7.00%
Minimum [Member]
Counterparty fuel mix:
Internal generation	40.00%	50.00%
Purchased power	40.00%	25.00%
Maximum [Member]
Counterparty fuel mix:
Internal generation	60.00%	75.00%
Purchased power	60.00%	50.00%

Fair Value of Financial Instr_6

Fair Value of Financial Instruments (Details-4) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019		Jun. 30, 2018
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance,	$ (31,283)	$ (41,463)	$ (32,002)		$ (42,026)
Realized and unrealized gains (losses):
Included in regulatory assets	(2,054)	4,130	(1,335)		4,693
Included in other comprehensive income	0	0	0		0
Included in earnings	(792)	82	(1,436)	[1]	(460)	[1]
Included in current assets	(376)	(297)	(203)		(470)
Purchases	5,858	6,032	11,623		11,866
Sales	0	0	0		0
Issuances	0	0	0		0
Settlements	(4,690)	(5,816)	(9,984)		(10,935)
Transfers in and/or out of level 3	0	0	0		0
Ending balance,	$ (33,337)	$ (37,332)	$ (33,337)		$ (37,332)
[1]	MGE's exchange-traded derivative contracts, over-the-counter party transactions, purchased power agreement, and FTRs are subject to regulatory deferral. These derivatives are therefore marked to fair value and are offset in the financial statements with a corresponding regulatory asset or liability.

Fair Value of Financial Instr_7

Fair Value of Financial Instruments (Details-5) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019		Jun. 30, 2018
Fair Value Disclosures [Abstract]
Total gains (losses) included in earnings attributed to the change in unrealized gains (losses) related to assets and liabilities	[1]	$ 0	$ 0	$ 0		$ 0
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Included in earnings		(792)	82	(1,436)	[1]	(460)	[1]
Purchased Power Expense [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Included in earnings		(693)	60	(1,249)	[1]	(663)	[1]
Cost Of Gas Sold Expense [Member]
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Included in earnings		$ (99)	$ 22	$ (187)	[1]	$ 203	[1]
[1]	MGE's exchange-traded derivative contracts, over-the-counter party transactions, purchased power agreement, and FTRs are subject to regulatory deferral. These derivatives are therefore marked to fair value and are offset in the financial statements with a corresponding regulatory asset or liability.

Asset Retirement Obligation (De

Asset Retirement Obligation (Details) $ in Millions	6 Months Ended
	Jun. 30, 2019USD ($)
Saratoga Wind Farm [Member]
Asset Retirement Obligations [Roll Forward]
Saratoga Wind Asset Retirement Obligation	$ 1.5

Joint Plant Ownership (Details)

Joint Plant Ownership (Details) - MGE [Member] $ in Millions	Jul. 31, 2019USD ($)MW	Jun. 30, 2019USD ($)MW
Two Creeks Units [Member]
Jointly Owned Utility Plant Interests [Line Items]
Jointly owned utility plant, ownership interest		33.00%
Jointly owned utility plant, plant capacity (in MW) | MW		150
Projected Solar Farm Project Costs		$ 65
Public Utilities Property Plant And Equipment Construction Work In Progress		16.5
Badger Hollow Units [Member]
Jointly Owned Utility Plant Interests [Line Items]
Public Utilities Property Plant And Equipment Construction Work In Progress		$ 1
Badger Hollow Units [Member] | Subsequent Event [Member]
Jointly Owned Utility Plant Interests [Line Items]
Jointly owned utility plant, ownership interest	33.00%
Jointly owned utility plant, plant capacity (in MW) | MW	150
Projected Solar Farm Project Costs	$ 65

Revenue (Details-1)

Revenue (Details-1) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Total Operating Revenue [Member]
Disaggregation of Revenue [Line Items]
Revenues recognized from contracts with customers	$ 122,147	$ 124,262	$ 289,716	$ 281,894
Electric [Member]
Disaggregation of Revenue [Line Items]
Revenues recognized from contracts with customers	96,863	99,067	194,279	193,458
Electric [Member] | Residential [Member]
Disaggregation of Revenue [Line Items]
Revenues recognized from contracts with customers	30,749	32,217	65,330	65,476
Electric [Member] | Commercial [Member]
Disaggregation of Revenue [Line Items]
Revenues recognized from contracts with customers	52,762	50,174	102,015	97,626
Electric [Member] | Industrial [Member]
Disaggregation of Revenue [Line Items]
Revenues recognized from contracts with customers	3,322	4,630	6,253	7,525
Electric [Member] | Other-retail/municipal
Disaggregation of Revenue [Line Items]
Revenues recognized from contracts with customers	8,946	8,527	17,185	16,814
Electric [Member] | Total Retail [Member]
Disaggregation of Revenue [Line Items]
Revenues recognized from contracts with customers	95,779	95,548	190,783	187,441
Electric [Member] | Sales To The Market [Member]
Disaggregation of Revenue [Line Items]
Revenues recognized from contracts with customers	790	2,795	2,751	4,829
Electric [Member] | Other Revenues [Member]
Disaggregation of Revenue [Line Items]
Revenues recognized from contracts with customers	294	724	745	1,188
Gas [Member]
Disaggregation of Revenue [Line Items]
Revenues recognized from contracts with customers	25,070	24,980	95,170	87,745
Gas [Member] | Residential [Member]
Disaggregation of Revenue [Line Items]
Revenues recognized from contracts with customers	16,000	15,620	56,317	52,171
Gas [Member] | Commercial/Industrial [Member]
Disaggregation of Revenue [Line Items]
Revenues recognized from contracts with customers	7,883	8,206	36,008	33,158
Gas [Member] | Total Retail [Member]
Disaggregation of Revenue [Line Items]
Revenues recognized from contracts with customers	23,883	23,826	92,325	85,329
Gas [Member] | Gas Transportation [Member]
Disaggregation of Revenue [Line Items]
Revenues recognized from contracts with customers	1,094	1,053	2,630	2,189
Gas [Member] | Other Revenues [Member]
Disaggregation of Revenue [Line Items]
Revenues recognized from contracts with customers	93	101	215	227
Non Regulated Energy [Member]
Disaggregation of Revenue [Line Items]
Revenues recognized from contracts with customers	$ 214	$ 215	$ 267	$ 691

Segment Information (Details)

Segment Information (Details) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Segment Reporting Information [Line Items]
Operating revenues	$ 122,147,000	$ 124,262,000	$ 289,716,000	$ 281,894,000
Depreciation and amortization	(18,091,000)	(13,872,000)	(35,230,000)	(27,495,000)
Other operating expenses	(84,273,000)	(86,159,000)	(204,193,000)	(203,980,000)
Operating income (loss)	19,783,000	24,231,000	50,293,000	50,419,000
Other income (deductions), net	5,019,000	4,731,000	9,870,000	9,650,000
Interest (expense) income, net	(5,749,000)	(4,783,000)	(11,396,000)	(9,522,000)
Income before income taxes	19,053,000	24,179,000	48,767,000	50,547,000
Income tax (provision) benefit	(3,505,000)	(5,828,000)	(9,213,000)	(12,195,000)
Net Income	15,548,000	18,351,000	39,554,000	38,352,000
Segment Reporting Assets And Capital Expenditures [Abstract]
Assets	2,026,086,000		2,026,086,000		$ 1,988,618,000
Capital expenditures			79,092,000	100,389,000	212,197,000
Electric [Member]
Segment Reporting Information [Line Items]
Operating revenues	96,863,000	99,067,000	194,279,000	193,458,000
Gas [Member]
Segment Reporting Information [Line Items]
Operating revenues	25,070,000	24,980,000	95,170,000	87,745,000
Non Regulated Energy [Member]
Segment Reporting Information [Line Items]
Operating revenues	214,000	215,000	267,000	691,000
Transmission Investment [Member]
Segment Reporting Information [Line Items]
Operating revenues	0	0	0	0
All Others [Member]
Segment Reporting Information [Line Items]
Operating revenues	0	0	0	0
Operating Segments [Member]
Segment Reporting Information [Line Items]
Operating revenues	122,147,000	124,262,000	289,716,000	281,894,000
Operating Segments [Member] | Electric [Member]
Segment Reporting Information [Line Items]
Operating revenues	97,061,000	98,822,000	194,676,000	193,244,000
Depreciation and amortization	(13,379,000)	(9,575,000)	(25,888,000)	(18,953,000)
Other operating expenses	(73,130,000)	(74,535,000)	(146,424,000)	(151,110,000)
Operating income (loss)	10,552,000	14,712,000	22,364,000	23,181,000
Other income (deductions), net	1,788,000	1,562,000	3,441,000	3,292,000
Interest (expense) income, net	(3,826,000)	(2,952,000)	(7,491,000)	(5,819,000)
Income before income taxes	8,514,000	13,322,000	18,314,000	20,654,000
Income tax (provision) benefit	(638,000)	(2,986,000)	(1,088,000)	(4,186,000)
Net Income	7,876,000	10,336,000	17,226,000	16,468,000
Segment Reporting Assets And Capital Expenditures [Abstract]
Assets	1,250,755,000		1,250,755,000		1,193,083,000
Capital expenditures			62,281,000		176,399,000
Operating Segments [Member] | Gas [Member]
Segment Reporting Information [Line Items]
Operating revenues	26,999,000	28,473,000	102,061,000	95,585,000
Depreciation and amortization	(2,843,000)	(2,445,000)	(5,603,000)	(4,840,000)
Other operating expenses	(22,931,000)	(24,232,000)	(84,369,000)	(79,427,000)
Operating income (loss)	1,225,000	1,796,000	12,089,000	11,318,000
Other income (deductions), net	1,170,000	752,000	1,724,000	1,518,000
Interest (expense) income, net	(1,032,000)	(887,000)	(2,072,000)	(1,726,000)
Income before income taxes	1,363,000	1,661,000	11,741,000	11,110,000
Income tax (provision) benefit	(412,000)	(372,000)	(3,031,000)	(2,830,000)
Net Income	951,000	1,289,000	8,710,000	8,280,000
Segment Reporting Assets And Capital Expenditures [Abstract]
Assets	369,467,000		369,467,000		377,005,000
Capital expenditures			15,028,000		30,497,000
Operating Segments [Member] | Non Regulated Energy [Member]
Segment Reporting Information [Line Items]
Operating revenues	10,209,000	10,062,000	20,235,000	20,358,000
Depreciation and amortization	(1,869,000)	(1,852,000)	(3,739,000)	(3,702,000)
Other operating expenses	(33,000)	(34,000)	(81,000)	(77,000)
Operating income (loss)	8,307,000	8,176,000	16,415,000	16,579,000
Other income (deductions), net	0	0	0	0
Interest (expense) income, net	(1,275,000)	(1,334,000)	(2,565,000)	(2,682,000)
Income before income taxes	7,032,000	6,842,000	13,850,000	13,897,000
Income tax (provision) benefit	(1,916,000)	(1,864,000)	(3,773,000)	(3,786,000)
Net Income	5,116,000	4,978,000	10,077,000	10,111,000
Segment Reporting Assets And Capital Expenditures [Abstract]
Assets	261,707,000		261,707,000		265,301,000
Capital expenditures			1,783,000		5,301,000
Operating Segments [Member] | Transmission Investment [Member]
Segment Reporting Information [Line Items]
Operating revenues	0	0	0	0
Depreciation and amortization	0	0	0	0
Other operating expenses	0	(5,000)	0	(8,000)
Operating income (loss)	0	(5,000)	0	(8,000)
Other income (deductions), net	2,267,000	1,916,000	4,436,000	4,288,000
Interest (expense) income, net	0	0	0	0
Income before income taxes	2,267,000	1,911,000	4,436,000	4,280,000
Income tax (provision) benefit	(619,000)	(522,000)	(1,210,000)	(1,170,000)
Net Income	1,648,000	1,389,000	3,226,000	3,110,000
Segment Reporting Assets And Capital Expenditures [Abstract]
Assets	68,350,000		68,350,000		66,366,000
Capital expenditures			0		0
Operating Segments [Member] | All Others [Member]
Segment Reporting Information [Line Items]
Operating revenues	0	0	0	0
Depreciation and amortization	0	0	0	0
Other operating expenses	(301,000)	(448,000)	(575,000)	(651,000)
Operating income (loss)	(301,000)	(448,000)	(575,000)	(651,000)
Other income (deductions), net	(206,000)	501,000	269,000	552,000
Interest (expense) income, net	384,000	390,000	732,000	705,000
Income before income taxes	(123,000)	443,000	426,000	606,000
Income tax (provision) benefit	80,000	(84,000)	(111,000)	(223,000)
Net Income	(43,000)	359,000	315,000	383,000
Segment Reporting Assets And Capital Expenditures [Abstract]
Assets	453,604,000		453,604,000		465,661,000
Capital expenditures			0		0
Consolidation Elimination Entries [Member]
Segment Reporting Information [Line Items]
Operating revenues	(12,122,000)	(13,095,000)	(27,256,000)	(27,293,000)
Depreciation and amortization	0	0	0	0
Other operating expenses	12,122,000	13,095,000	27,256,000	27,293,000
Operating income (loss)	0	0	0	0
Other income (deductions), net	0	0	0	0
Interest (expense) income, net	0	0	0	0
Income before income taxes	0	0	0	0
Income tax (provision) benefit	0	0	0	0
Net Income	0	0	0	0
Segment Reporting Assets And Capital Expenditures [Abstract]
Assets	(377,797,000)		(377,797,000)		(378,798,000)
Capital expenditures			0		0
Consolidation Elimination Entries [Member] | Electric [Member]
Segment Reporting Information [Line Items]
Operating revenues	198,000	(245,000)	397,000	(214,000)
Consolidation Elimination Entries [Member] | Gas [Member]
Segment Reporting Information [Line Items]
Operating revenues	1,929,000	3,493,000	6,891,000	7,840,000
Consolidation Elimination Entries [Member] | Non Regulated Energy [Member]
Segment Reporting Information [Line Items]
Operating revenues	9,995,000	9,847,000	19,968,000	19,667,000
Consolidation Elimination Entries [Member] | Transmission Investment [Member]
Segment Reporting Information [Line Items]
Operating revenues	0	0	0	0
Consolidation Elimination Entries [Member] | All Others [Member]
Segment Reporting Information [Line Items]
Operating revenues	0	0	0	0
MGE [Member]
Segment Reporting Information [Line Items]
Operating revenues	122,147,000	124,262,000	289,716,000	281,894,000
Depreciation and amortization	(18,091,000)	(13,872,000)	(35,230,000)	(27,495,000)
Other operating expenses	(83,972,000)	(85,707,000)	(203,618,000)	(203,322,000)
Operating income (loss)	20,084,000	24,683,000	50,868,000	51,077,000
Other income (deductions), net	2,958,000	2,314,000	5,165,000	4,811,000
Interest (expense) income, net	(6,133,000)	(5,173,000)	(12,128,000)	(10,227,000)
Income before income taxes	16,909,000	21,824,000	43,905,000	45,661,000
Income tax (provision) benefit	(2,966,000)	(5,221,000)	(7,892,000)	(10,802,000)
Net Income Including Noncontrolling Interest	13,943,000	16,603,000	36,013,000	34,859,000
Less Net Income Attributable to Noncontrolling Interest, net of tax	(5,621,000)	(5,505,000)	(11,111,000)	(11,311,000)
Net Income	8,322,000	11,098,000	24,902,000	23,548,000
Segment Reporting Assets And Capital Expenditures [Abstract]
Assets	1,881,666,000		1,881,666,000		1,834,891,000
Capital expenditures			79,092,000	100,389,000	212,197,000
MGE [Member] | Electric [Member]
Segment Reporting Information [Line Items]
Operating revenues	96,863,000	99,067,000	194,279,000	193,458,000
MGE [Member] | Gas [Member]
Segment Reporting Information [Line Items]
Operating revenues	25,070,000	24,980,000	95,170,000	87,745,000
MGE [Member] | Non Regulated Energy [Member]
Segment Reporting Information [Line Items]
Operating revenues	214,000	215,000	267,000	691,000
MGE [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Operating revenues	122,147,000	124,262,000	289,716,000	281,894,000
MGE [Member] | Operating Segments [Member] | Electric [Member]
Segment Reporting Information [Line Items]
Operating revenues	97,061,000	98,822,000	194,676,000	193,244,000
Depreciation and amortization	(13,379,000)	(9,575,000)	(25,888,000)	(18,953,000)
Other operating expenses	(73,130,000)	(74,535,000)	(146,424,000)	(151,110,000)
Operating income (loss)	10,552,000	14,712,000	22,364,000	23,181,000
Other income (deductions), net	1,788,000	1,561,000	3,441,000	3,292,000
Interest (expense) income, net	(3,826,000)	(2,952,000)	(7,491,000)	(5,819,000)
Income before income taxes	8,514,000	13,321,000	18,314,000	20,654,000
Income tax (provision) benefit	(638,000)	(2,985,000)	(1,088,000)	(4,186,000)
Net Income Including Noncontrolling Interest	7,876,000	10,336,000	17,226,000	16,468,000
Less Net Income Attributable to Noncontrolling Interest, net of tax	0	0	0	0
Net Income	7,876,000	10,336,000	17,226,000	16,468,000
Segment Reporting Assets And Capital Expenditures [Abstract]
Assets	1,250,755,000		1,250,755,000		1,193,083,000
Capital expenditures			62,281,000		176,399,000
MGE [Member] | Operating Segments [Member] | Gas [Member]
Segment Reporting Information [Line Items]
Operating revenues	26,999,000	28,473,000	102,061,000	95,585,000
Depreciation and amortization	(2,843,000)	(2,445,000)	(5,603,000)	(4,840,000)
Other operating expenses	(22,931,000)	(24,232,000)	(84,369,000)	(79,427,000)
Operating income (loss)	1,225,000	1,796,000	12,089,000	11,318,000
Other income (deductions), net	1,170,000	753,000	1,724,000	1,519,000
Interest (expense) income, net	(1,032,000)	(887,000)	(2,072,000)	(1,726,000)
Income before income taxes	1,363,000	1,662,000	11,741,000	11,111,000
Income tax (provision) benefit	(412,000)	(373,000)	(3,031,000)	(2,831,000)
Net Income Including Noncontrolling Interest	951,000	1,289,000	8,710,000	8,280,000
Less Net Income Attributable to Noncontrolling Interest, net of tax	0	0	0	0
Net Income	951,000	1,289,000	8,710,000	8,280,000
Segment Reporting Assets And Capital Expenditures [Abstract]
Assets	369,467,000		369,467,000		377,005,000
Capital expenditures			15,028,000		30,497,000
MGE [Member] | Operating Segments [Member] | Non Regulated Energy [Member]
Segment Reporting Information [Line Items]
Operating revenues	10,209,000	10,062,000	20,235,000	20,358,000
Depreciation and amortization	(1,869,000)	(1,852,000)	(3,739,000)	(3,702,000)
Other operating expenses	(33,000)	(35,000)	(81,000)	(78,000)
Operating income (loss)	8,307,000	8,175,000	16,415,000	16,578,000
Other income (deductions), net	0	0	0	0
Interest (expense) income, net	(1,275,000)	(1,334,000)	(2,565,000)	(2,682,000)
Income before income taxes	7,032,000	6,841,000	13,850,000	13,896,000
Income tax (provision) benefit	(1,916,000)	(1,863,000)	(3,773,000)	(3,785,000)
Net Income Including Noncontrolling Interest	5,116,000	4,978,000	10,077,000	10,111,000
Less Net Income Attributable to Noncontrolling Interest, net of tax	0	0	0	0
Net Income	5,116,000	4,978,000	10,077,000	10,111,000
Segment Reporting Assets And Capital Expenditures [Abstract]
Assets	261,657,000		261,657,000		265,251,000
Capital expenditures			1,783,000		5,301,000
MGE [Member] | Consolidation Elimination Entries [Member]
Segment Reporting Information [Line Items]
Operating revenues	(12,122,000)	(13,095,000)	(27,256,000)	(27,293,000)
Depreciation and amortization	0	0	0	0
Other operating expenses	12,122,000	13,095,000	27,256,000	27,293,000
Operating income (loss)	0	0	0	0
Other income (deductions), net	0	0	0	0
Interest (expense) income, net	0	0	0	0
Income before income taxes	0	0	0	0
Income tax (provision) benefit	0	0	0	0
Net Income Including Noncontrolling Interest	0	0	0	0
Less Net Income Attributable to Noncontrolling Interest, net of tax	(5,621,000)	(5,505,000)	(11,111,000)	(11,311,000)
Net Income	(5,621,000)	(5,505,000)	(11,111,000)	(11,311,000)
Segment Reporting Assets And Capital Expenditures [Abstract]
Assets	(213,000)		(213,000)		(448,000)
Capital expenditures			0		$ 0
MGE [Member] | Consolidation Elimination Entries [Member] | Electric [Member]
Segment Reporting Information [Line Items]
Operating revenues	198,000	(245,000)	397,000	(214,000)
MGE [Member] | Consolidation Elimination Entries [Member] | Gas [Member]
Segment Reporting Information [Line Items]
Operating revenues	1,929,000	3,493,000	6,891,000	7,840,000
MGE [Member] | Consolidation Elimination Entries [Member] | Non Regulated Energy [Member]
Segment Reporting Information [Line Items]
Operating revenues	$ 9,995,000	$ 9,847,000	$ 19,968,000	$ 19,667,000