EMPLOYEE BENEFIT PLANS (Tables)

12 Months Ended

Dec. 31, 2017

Summary of target asset allocation percentages for major categories of the pension plan

The Company's target asset allocation percentages for major categories of the pension plan are reflected in the table below:



	Minimum Exposure		Target		Maximum Exposure
Fixed Income	35	%	40	%	45	%
Total Domestic Equity:	40	%	50	%	60	%
Small Cap Stocks	10	%	15	%	20	%
Large Cap Stocks	30	%	35	%	45	%
Non-U.S. Equities	5	%	10	%	15	%

Schedule of fair value plan assets

All Plan investments are level one investments in mutual funds and are valued at the net asset value (NAV) of the shares held at December 31, 2017 and 2016:



	Pension Benefits								Other Benefits
	2017		%		2016		%		2017		%		2016		%
Fixed Income	$	171,403	37	%	$	141,576	38	%	$	60,438	60	%	$	54,166	63	%
Domestic Equity: Small Cap Stocks	73,682		16	%	61,036		16	%	—		—		—		—
Domestic Equity: Large Cap Stocks	169,661		37	%	136,405		36	%	40,125		40	%	32,412		37	%
Non U.S. Equities	46,132		10	%	37,532		10	%	—		—		—		—
Total Plan Assets	$	460,878	100	%	$	376,549	100	%	$	100,563	100	%	$	86,578	100	%

Schedule of reconciliation of the funded status of the plans with the accrued pension liability and the net postretirement benefit liability

The following table reconciles the funded status of the plans with the accrued pension liability and the net postretirement benefit liability as of December 31, 2017 and 2016:



	Pension Benefits						Other Benefits
	2017			2016			2017			2016
Change in projected benefit obligation:
Beginning of year	$	564,755		$	501,879		$	122,108		$	136,736
Service cost	23,801			20,971			7,152			6,513
Interest cost	23,256			22,226			4,988			4,863
Assumption change	60,526			15,599			15,298			(8,748		)
Experience loss	10,836			14,075			(4,546		)	(16,041		)
Benefits paid, net of retiree premiums	(11,840		)	(9,995		)	(1,632		)	(1,215		)
End of year	$	671,334		$	564,755		$	143,368		$	122,108
Change in plan assets:
Fair value of plan assets at beginning of year	$	376,549		$	328,634		$	86,578		$	72,886
Actual return on plan assets	64,365			27,916			6,508			5,342
Employer contributions	31,804			29,994			9,109			9,565
Retiree contributions and Medicare part D subsidies	—			—			1,884			1,611
Benefits paid	(11,840		)	(9,995		)	(3,516		)	(2,826		)
Fair value of plan assets at end of year	$	460,878		$	376,549		$	100,563		$	86,578
Funded status(1)	$	(210,456	)	$	(188,206	)	$	(42,805	)	$	(35,530	)
Unrecognized actuarial loss	150,545			126,610			39,796			31,821
Unrecognized prior service cost	20,342			26,123			165			207
Net amount recognized	$	(39,569	)	$	(35,473	)	$	(2,844	)	$	(3,502	)

_______________________________________________________________________________


(1)	The short-term portion of the pension benefits was $2.0 million as of December 31, 2017 and 2016.

Schedule of amounts recognized in consolidated balance sheets

Amounts recognized on the balance sheet consist of:



	Pension Benefits						Other Benefits
	2017			2016			2017			2016
(Accrued) benefit costs	$	60		$	—		$	(3,461	)	$	(4,119	)
Accrued benefit liability	(210,456		)	(188,206		)	(42,805		)	(35,530		)
Regulatory asset	170,827			152,733			43,422			36,147
Net amount recognized	$	(39,569	)	$	(35,473	)	$	(2,844	)	$	(3,502	)

Schedule of actuarial assumptions used in determining the benefit obligation

Below are the actuarial assumptions used in determining the benefit obligation for the benefit plans:



	Pension Benefits				Other Benefits
	2017		2016		2017		2016
Weighted average assumptions as of December 31:
Discount rate	3.60	%	4.15	%	3.65	%	4.25	%
Long-term rate of return on plan assets	6.50	%	6.50	%	5.50	%	5.50	%
Rate of compensation increases	3.25	%	3.25	%	—		—
Cost of living adjustment	2.50	%	2.50	%	—		—

Schedule of components of net periodic benefit costs for the pension plans and other postretirement benefits

Net periodic benefit costs for the pension and other postretirement plans for the years ended December 31, 2017, 2016, and 2015 included the following components:



	Pension Plan									Other Benefits
	2017			2016			2015			2017			2016			2015
Service cost	$	23,801		$	20,971		$	21,306		$	7,152		$	6,513		$	8,476
Interest cost	23,256			22,226			20,104			4,988			4,863			5,654
Expected return on plan assets	(24,119		)	(21,826		)	(19,138		)	(4,875		)	(4,129		)	(3,519		)
Net amortization and deferral	12,962			11,990			15,485			1,186			1,660			4,536
Net periodic benefit cost	$	35,900		$	33,361		$	37,757		$	8,451		$	8,907		$	15,147

Schedule of actuarial assumptions used in determining the net periodic benefit costs

Below are the actuarial assumptions used in determining the net periodic benefit costs for the benefit plans, which uses the end of the prior year as the measurement date:



	Pension Benefits				Other Benefits
	2017		2016		2017		2016
Weighted average assumptions as of December 31:
Discount rate	4.15	%	4.40	%	4.25	%	4.40	%
Long-term rate of return on plan assets	6.50	%	6.50	%	5.50	%	5.50	%
Rate of compensation increases	3.25	%	3.25	%	—		—

Schedule of the effect of a one-percentage point change in assumed health care cost trends

A 1-percentage point change in assumed health care cost trends is estimated to have the following effect:



	1-Percentage Point Increase		1-Percentage Point (Decrease)
Effect on total service and interest costs	$	3,919	$	(2,795	)
Effect on accumulated postretirement benefit obligation	$	39,117	$	(28,762	)