Pension and Other Postretirement Plans (Tables)

3 Months Ended

Mar. 31, 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 months endedMarch 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