Pension and Other Postretirement Plans

9 Months Ended

Sep. 30, 2018

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.

The components of net periodic benefit cost, other than the service cost component, are recorded in "Other income, net" on the consolidated statements of income. The service cost component is recorded in "Other operations and maintenance" on the consolidated statements of income. Prior to January 1, 2018, a portion of all net periodic benefit cost components were capitalized within the consolidated balance sheets. The FASB issued authoritative guidance within the codification's Compensation-Retirement Benefits topic that, beginning January 1, 2018, only allows the service cost component of net periodic benefit cost to be eligible for capitalization within the consolidated balance sheets. MGE has regulatory treatment and recognizes regulatory assets or liabilities for timing differences between when net periodic benefit costs are recovered and when costs are recognized.

The following table presents the components of net periodic benefit costs recognized for the three and nine months ended September 30, 2018 and 2017.

		Three Months Ended				Nine Months Ended
		September 30,				September 30,
(In thousands)		2018		2017		2018		2017
Pension Benefits
Components of net periodic benefit cost:
Service cost	$	1,431	$	1,351	$	4,292	$	4,043
Interest cost		3,215		3,168		9,645		9,481
Expected return on assets		(6,560)		(5,762)		(19,680)		(17,244)
Amortization of:
Prior service credit		(11)		(4)		(33)		(12)
Actuarial loss		1,319		1,594		3,958		4,769
Net periodic benefit (credit) cost	$	(606)	$	347	$	(1,818)	$	1,037

Postretirement Benefits
Components of net periodic benefit cost:
Service cost	$	320	$	315	$	962	$	944
Interest cost		653		678		1,959		2,034
Expected return on assets		(808)		(722)		(2,424)		(2,165)
Amortization of:
Transition obligation		1		1		2		2
Prior service credit		(667)		(667)		(2,001)		(2,001)
Actuarial loss		122		190		366		570
Net periodic benefit (credit) cost	$	(379)	$	(205)	$	(1,136)	$	(616)