10. EMPLOYEE BENEFIT PLANS

Pension and Other Postemployment Benefit Plans

The components of the net periodic cost for pension benefits, including the Company's Pension Equalization Plan, and OPEB costs (principally health care and life insurance) for employees and covered dependents were as follows:



	Pension												OPEB
	Three Months Ended						Nine Months Ended						Three Months Ended						Nine Months Ended
	June 30,						June 30,						June 30,						June 30,
(Thousands)	2018			2017			2018			2017			2018			2017			2018			2017
Service cost	$	2,035		$	2,086		$	6,104		$	6,260		$	1,152		$	1,095		$	3,455		$	3,285
Interest cost	2,623			2,443			7,870			7,328			1,591			1,386			4,773			4,159
Expected return on plan assets	(4,910		)	(4,829		)	(14,729		)	(14,485		)	(1,338		)	(1,192		)	(4,014		)	(3,575		)
Recognized actuarial loss	1,884			2,207			5,653			6,620			1,165			1,093			3,495			3,278
Prior service cost amortization	27			28			80			83			(91		)	(91		)	(273		)	(273		)
Net periodic benefit cost	$	1,659		$	1,935		$	4,978		$	5,806		$	2,479		$	2,291		$	7,436		$	6,874

The Company does not expect to be required to make additional contributions to fund the pension plans during fiscal 2018 or 2019 based on current actuarial assumptions; however, funding requirements are uncertain and can depend significantly on changes in actuarial assumptions, returns on plan assets and changes in the demographics of eligible employees and covered dependents. In addition, as in the past, the Company may elect to make contributions in excess of the minimum required amount to the plans. There were no discretionary contributions made during the nine months ended June 30, 2018.

In April 2018, the Company implemented a voluntary early retirement program open to certain eligible employees. The Company expects to recognize an expense of approximately $6.4 million for related postemployment benefit costs and other termination benefits, of which $4.6 million was recognized during the nine months ended June 30, 2018, as a component of O&M in the Unaudited Condensed Consolidated Statements of Operations.