Components of Periodic Benefit Costs

The Bank has a defined benefit pension plan (the "Pension Plan") covering its full-time employees who satisfy the eligibility requirements. The benefits are based on years of service and the employee's compensation during the last five years of employment. Costs of the Pension Plan, based on the actuarial computations of the current future benefits for employees, are recognized to expense and are funded in part based on the maximum amount that can be deducted for federal income tax purposes. The Pension Plan’s assets are primarily invested in fixed debt and equity securities.

In addition to the Pension Plan, certain health care and life insurance benefits are made available to retirement employees (the "Post-retirement Plan").

The Bank has a retirement income maintenance plan (the "RIM Plan"). The RIM Plan is a non-qualified defined benefit plan which provides benefits to all employees of the Bank if their benefits under the Pension Plan are limited by the Internal Revenue Code Sections 415 and 401(a)(17).

Net periodic benefit cost (income) for pension benefits and other benefits for the three and six months ended March 31, 2018 and 2017 includes the following components:



	For the Three Months Ended March 31,
	Pension						RIM				Post-retirement
	2018			2017			2018		2017		2018			2017
	(In thousands)
Service cost	$	1,780		$	1,905		$	61	$	59	$	93		$	118
Interest cost	2,129			2,111			111		107		205			186
Expected return on plan assets	(4,815		)	(6,202		)	—		—		—			—
Amortization:
Prior service cost	—			—			—		—		(34		)	(34		)
Net loss	707			2,750			103		113		69			81
Net periodic cost (income)	$	(199	)	$	564		$	275	$	279	$	333		$	351



	For the Six Months Ended March 31,
	Pension				RIM		Post-retirement
	2018		2017		2018	2017	2018		2017
	(In thousands)
Service cost	3,560		3,811		122	119	186		236
Interest cost	4,258		4,222		222	215	410		371
Expected return on plan assets	(9,630	)	(12,405	)	—	—	—		—
Amortization:
Prior service cost	—		—		—	—	(68	)	(68	)
Net loss	1,414		5,499		206	227	138		163
Net periodic cost (income)	(398	)	1,127		550	561	666		702

The net periodic benefit cost (income) for pension benefits and other benefits at March 31, 2018 were calculated using the December 31, 2017 third party actuarial valuation reports. For March 31, 2017, the September 30, 2017 third party actuarial valuation reports were utilized as a proxy to estimate the net periodic benefit cost for pension benefits.