Pension and Other Postretirement Plans (Tables)

9 Months Ended

Sep. 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 nine months endedSeptember 30,2015 and 2014. 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)		2015		2014		2015		2014
Pension Benefits
Components of net periodic (benefit) cost:
Service cost	$	1,878	$	1,536	$	5,715	$	4,609
Interest cost		3,594		3,367		10,936		10,102
Expected return on assets		(5,930)		(5,467)		(18,045)		(16,402)
Amortization of:
Prior service cost		6		51		18		152
Actuarial loss		1,393		180		4,240		539
Net periodic (benefit) cost	$	941	$	(333)	$	2,864	$	(1,000)
Postretirement Benefits
Components of net periodic (benefit) cost:
Service cost	$	194	$	241	$	580	$	722
Interest cost		392		564		1,176		1,691
Expected return on assets		(355)		(478)		(1,063)		(1,432)
Amortization of:
Transition obligation		-		1		1		2
Prior service benefit		(337)		(487)		(1,009)		(1,462)
Actuarial loss		133		28		397		86
Net periodic (benefit) cost	$	27	$	(131)	$	82	$	(393)