Pension and Other Postretirement Plans (Tables)

9 Months Ended

Sep. 30, 2016

Compensation and Retirement Disclosure [Abstract]

Schedule of Net Periodic Benefit Costs

The following table presents the components of MGE Energy's and MGE's net periodic benefit costs recognized for the three and nine months endedSeptember 30,2016 and 2015. A portion of the net periodic benefit cost is capitalized within the consolidated balance sheets.

		Three Months Ended				Nine Months Ended
		September 30,				September 30,
(In thousands)		2016		2015		2016		2015
Pension Benefits
Components of net periodic cost:
Service cost	$	1,413	$	1,878	$	4,358	$	5,715
Interest cost		3,161		3,594		9,744		10,936
Expected return on assets		(5,724)		(5,930)		(17,646)		(18,045)
Amortization of:
Prior service cost		3		6		8		18
Actuarial loss		1,388		1,393		4,278		4,240
Net periodic cost	$	241	$	941	$	742	$	2,864
Postretirement Benefits
Components of net periodic (benefit) cost:
Service cost	$	361	$	194	$	1,084	$	580
Interest cost		753		392		2,258		1,176
Expected return on assets		(787)		(355)		(2,360)		(1,063)
Amortization of:
Transition obligation		1		-		3		1
Prior service benefit		(744)		(337)		(2,233)		(1,009)
Actuarial loss		178		133		533		397
Net periodic (benefit) cost	$	(238)	$	27	$	(715)	$	82