Employee Benefit Plans:

9 Months Ended

Sep. 30, 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 SERP for the three and nine months ended September 30, 2016 and 2015 are as follows:



	For The Three Months Ended September 30,
	Pension Benefits						Other Postretirement Benefits						SERP
(dollars in thousands)	2016			2015			2016			2015			2016		2015
Components of Net Periodic Benefits Cost:
Service cost	$	1,274		$	1,569		$	68		$	65		$	200	$	204
Interest cost	1,978			1,922			97			99			186		163
Expected return on plan assets	(2,457		)	(2,449		)	(122		)	(123		)	—		—
Amortization of prior service cost (benefit)	12			30			(9		)	(50		)	6		29
Amortization of actuarial (gain) loss	228			448			(150		)	(131		)	73		108
Net periodic pension cost under accounting standards	1,035			1,520			(116		)	(140		)	465		504
Regulatory adjustment — deferred	221			130			—			—			—		—
Total expense recognized, before allocation to overhead pool	$	1,256		$	1,650		$	(116	)	$	(140	)	$	465	$	504



	For The Nine Months Ended September 30,
	Pension Benefits						Other Postretirement Benefits						SERP
(dollars in thousands)	2016			2015			2016			2015			2016		2015
Components of Net Periodic Benefits Cost:
Service cost	$	3,822		$	4,707		$	204		$	255		$	600	$	612
Interest cost	5,934			5,766			291			327			558		489
Expected return on plan assets	(7,377		)	(7,347		)	(366		)	(369		)	—		—
Amortization of prior service cost (benefit)	36			90			(27		)	(150		)	18		87
Amortization of actuarial (gain) loss	684			1,344			(450		)	(237		)	219		324
Net periodic pension cost under accounting standards	3,099			4,560			(348		)	(174		)	1,395		1,512
Regulatory adjustment — deferred	644			392			—			—			—		—
Total expense recognized, before allocation to overhead pool	$	3,743		$	4,952		$	(348	)	$	(174	)	$	1,395	$	1,512

During the three and nine months ended September 30, 2016, Registrant contributed $5.3 million to its pension plan.

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 September 30, 2016, GSWC had a total $1.5 million net under-collection in the two-way pension balancing accounts included as part of the pension regulatory asset (Note 2).