Employee Benefit Plans:

3 Months Ended

Mar. 31, 2016

Compensation and Retirement Disclosure [Abstract]

Employee Benefit Plans:

The components of net periodic benefit costs, before allocation to the overhead pool, for Registrant’s pension plan, postretirement plan and Supplemental Executive Retirement Plan ("SERP") for the three months ended March 31, 2016 and 2015 are as follows:



	For The Three Months Ended March 31,
	Pension Benefits						Other Postretirement Benefits						SERP
(dollars in thousands)	2016			2015			2016			2015			2016		2015
Components of Net Periodic Benefits Cost:
Service cost	$	1,232		$	1,686		$	68		$	95		$	200	$	204
Interest cost	1,930			1,939			97			114			186		163
Expected return on plan assets	(2,460		)	(2,446		)	(122		)	(123		)	—		—
Amortization of transition	—			—			—			—			—		—
Amortization of prior service cost (benefit)	12			30			(9		)	(50		)	6		29
Amortization of actuarial (gain) loss	127			469			(150		)	(53		)	73		108
Net periodic pension cost under accounting standards	841			1,678			(116		)	(17		)	465		504
Regulatory adjustment — deferred	359			11			—			—			—		—
Total expense recognized, before allocation to overhead pool	$	1,200		$	1,689		$	(116	)	$	(17	)	$	465	$	504

Registrant expects to contribute approximately $5.5 million to its pension plan during 2016.

During 2015, Registrant updated key assumptions used for the valuation of the pension, post-retirement and supplemental executive retirement plans. These updates included: (i) an increase in the discount rates; (ii) updates in demographic assumptions, such as retirement and termination rates, to reflect recent changes in participant behavior, and (iii) salary increases based on Registrant’s recent and future expected experience. As a result of these updates in actuarial assumptions, as well as the pension plan closure to new employees hired after December 31, 2010, net periodic benefit costs decreased for the three months ended March 31, 2016 as compared to the same period in 2015.

Regulatory Adjustment:

As authorized by the CPUC in the most recent water and electric general rate case decisions, GSWC utilizes two-way balancing accounts for its water and electric regions and the general office to track differences between the forecasted annual pension expenses in rates or expected to be in rates and the actual annual expense recorded by GSWC in accordance with the accounting guidance for pension costs. As of March 31, 2016, GSWC has a total $1.8 million net under-collection in the two-way pension balancing accounts included as part of the pension regulatory asset (Note 2).