Pension and Other Postretirement Plans (Tables)

6 Months Ended

Jun. 30, 2015

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 30,2015 and 2014. 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)		2015		2014		2015		2014
Pension Benefits
Components of net periodic (benefit) cost:
Service cost	$	2,039	$	1,589	$	3,837	$	3,073
Interest cost		3,902		3,483		7,342		6,735
Expected return on assets		(6,438)		(5,656)		(12,115)		(10,935)
Amortization of:
Prior service cost		6		53		12		102
Actuarial loss		1,513		186		2,847		358
Net periodic (benefit) cost	$	1,022	$	(345)	$	1,923	$	(667)
Postretirement Benefits
Components of net periodic (benefit) cost:
Service cost	$	3	$	152	$	386	$	482
Interest cost		6		356		784		1,127
Expected return on assets		(5)		(301)		(708)		(955)
Amortization of:
Transition obligation		-		-		1		1
Prior service benefit		(5)		(307)		(672)		(974)
Actuarial loss		2		17		264		57
Net periodic (benefit) cost	$	1	$	(83)	$	55	$	(262)