Pension and Other Postretirement Plans

3 Months Ended

Mar. 31, 2016

Compensation and Retirement Disclosure [Abstract]

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. MGE refined its methodology for using discount rates to measure the components of net periodic benefit cost for 2016. The refined methodology uses individual spot rates, instead of a weighted average of the yield curve spot rates, for measuring the service cost and interest cost components.

The following table presents the components of MGE Energy's and MGE's net periodic benefit costs recognized for the three months ended March 31, 2016 and 2015. A portion of the net periodic benefit cost is capitalized within the consolidated balance sheets.

		Three Months Ended
		March 31,
(In thousands)		2016		2015
Pension Benefits
Components of net periodic cost:
Service cost	$	1,381	$	1,798
Interest cost		3,089		3,440
Expected return on assets		(5,593)		(5,677)
Amortization of:
Prior service cost		2		6
Actuarial loss		1,356		1,334
Net periodic cost	$	235	$	901

Postretirement Benefits
Components of net periodic (benefit) cost:
Service cost	$	324	$	383
Interest cost		674		778
Expected return on assets		(705)		(703)
Amortization of:
Transition obligation		1		1
Prior service benefit		(667)		(667)
Actuarial loss		159		262
Net periodic (benefit) cost	$	(214)	$	54