Pension and Other Postretirement Plans (Tables)

6 Months Ended

Jun. 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 six months endedJune 30,2016 and 2015. A portion of the net periodic benefit cost is capitalized within the consolidated balance sheets.

		Three Months Ended				Six Months Ended
		June 30,				June 30,
(In thousands)		2016		2015		2016		2015
Pension Benefits
Components of net periodic cost:
Service cost	$	1,564	$	2,039	$	2,945	$	3,837
Interest cost		3,494		3,902		6,583		7,342
Expected return on assets		(6,329)		(6,438)		(11,922)		(12,115)
Amortization of:
Prior service cost		3		6		5		12
Actuarial loss		1,534		1,513		2,890		2,847
Net periodic cost	$	266	$	1,022	$	501	$	1,923
Postretirement Benefits
Components of net periodic (benefit) cost:
Service cost	$	399	$	3	$	723	$	386
Interest cost		831		6		1,505		784
Expected return on assets		(868)		(5)		(1,573)		(708)
Amortization of:
Transition obligation		1		-		2		1
Prior service benefit		(822)		(5)		(1,489)		(672)
Actuarial loss		196		2		355		264
Net periodic (benefit) cost	$	(263)	$	1	$	(477)	$	55