EMPLOYEE BENEFITS (Tables)

12 Months Ended

Dec. 31, 2015

Compensation and Retirement Disclosure [Abstract]

Summary of Actual and Target Asset Allocation of Plan Assets

The following is a summary of the pension plan's actual and target asset allocations at December 31, 2015 and 2014 by asset category:

									Target
Pension Plan Assets	2015		% of Total		2014		% of Total		Allocation
Fixed maturity securities - corporate bonds	$	6,894	6.5	%	$	9,035	8.8	%	0	%	-	15	%
Redeemable preferred stock	3,744		3.5		2,254		2.2		0	%	-	10	%
Equity securities	58,613		55.0		58,223		56.6		50	%	-	70	%
Pooled separate accounts
Core Plus Bond separate account fund	6,605		6.2		6,417		6.3		0	%	-	40	%
U.S. property separate account fund	11,252		10.5		9,895		9.6		0	%	-	25	%
Arbitrage fund	7,856		7.4		7,637		7.4		0	%	-	10	%
United Life annuity	8,931		8.4		8,506		8.3		5	%	-	10	%
Cash and cash equivalents	2,705		2.5		833		0.8		0	%	-	10	%
Total plan assets	$	106,600	100.0	%	$	102,800	100.0	%

Categories of Pension Plan Assets at Fair Value on Recurring Basis

The following tables present the categorization of the pension plan's assets measured at fair value on a recurring basis at December 31, 2015 and 2014:

			Fair Value Measurements
Description	December 31, 2015		Level 1		Level 2		Level 3
Fixed maturity securities - corporate bonds	$	6,894	$	—	$	6,894	$	—
Redeemable preferred stock	3,744		3,744		—		—
Equity securities	58,613		58,613		—		—
Pooled separate accounts
Core plus bond separate account fund	6,605		—		6,605		—
U.S. property separate account fund	11,252		—		—		11,252
Arbitrage fund	7,856		—		7,856		—
Money market funds	2,619		2,619		—		—
Total assets measured at fair value	$	97,583	$	64,976	$	21,355	$	11,252

			Fair Value Measurements
Description	December 31, 2014		Level 1		Level 2		Level 3
Fixed maturity securities - corporate bonds	$	9,035	$	—	$	9,035	$	—
Redeemable preferred stock	2,254		2,254		—		—
Equity securities	58,223		58,223		—		—
Pooled separate accounts
Core plus bond separate account fund	6,417		—		6,417		—
U.S. property separate account fund	9,895		—		—		9,895
Arbitrage fund	7,637		—		7,637		—
Money market funds	826		826		—		—
Total assets measured at fair value	$	94,287	$	61,303	$	23,089	$	9,895

Summary of Changes in Fair Value of Pension Plan Securities

The following tables provide a summary of the changes in fair value of the pension plan's Level 3 securities:

	U.S. property separate account fund
Balance at January 1, 2015	$	9,895
Unrealized gains	1,357
Balance at December 31, 2015	$	11,252

	U.S. property separate account fund
Balance at January 1, 2014	$	8,763
Unrealized gains	1,132
Balance at December 31, 2014	$	9,895

Schedule of Actuarial Assumptions Used

The following actuarial assumptions were used to determine the reported plan benefit obligations at December 31:

Weighted-average assumptions as of	Pension Benefits				Postretirement Benefits
December 31,	2015		2014		2015		2014
Discount rate	4.21	%	3.86	%	4.21	%	3.86	%
Rate of compensation increase	3.00		3.00		N/A		N/A

The following actuarial assumptions were used at January 1 to determine our reported net periodic benefit costs for the year ended December 31:

Weighted-average assumptions as of	Pension Benefits						Postretirement Benefits
January 1,	2015		2014		2013		2015		2014		2013
Discount rate	3.86	%	4.84	%	4.00	%	3.86	%	4.84	%	4.00	%
Expected long-term rate of return on plan assets	7.50		7.50		7.50		N/A		N/A		N/A
Rate of compensation increase	3.00		3.50		3.50		N/A		N/A		N/A

Schedule of Health Care Cost Trend Rates

	Health Care Benefits				Dental Claims
Years Ended December 31,	2015		2014		2015		2014
Health care cost trend rates assumed for next year	7.00	%	7.00	%	4.00	%	4.00	%
Rate to which the health care trend rate is assumed to decline (ultimate trend rate)	4.50	%	4.50	%	N/A		N/A
Year that the rate reaches the ultimate trend rate	2024		2023		N/A		N/A

Schedule of Effect of One-Percentage-Point Change in Assumed Health Care Cost Trend Rates

A 1.0 percent change in assumed health care cost trend rates would have the following effects:

	1% Increase		1% Decrease
Effect on the net periodic postretirement health care benefit cost	$	1,595	$	(1,239	)
Effect on the accumulated postretirement benefit obligation	14,178		(11,270		)

Reconciliation of Benefit Obligations, Plan Assets, and Funded Status

The following table provides a reconciliation of benefit obligations, plan assets and funded status of our plans:

	Pension Benefits						Postretirement Benefits
Years Ended December 31,	2015			2014			2015			2014
Reconciliation of benefit obligation
Benefit obligation at beginning of year	$	157,600		$	123,352		$	74,552		$	48,954
Service cost	6,675			5,210			5,220			3,696
Interest cost	5,999			5,874			2,856			2,342
Actuarial (gain) loss	(5,678		)	26,590			(9,253		)	20,730
Benefit payments and adjustments	(4,206		)	(3,426		)	(1,200		)	(1,170		)
Benefit obligation at end of year (1)	$	160,390		$	157,600		$	72,175		$	74,552
Reconciliation of fair value of plan assets
Fair value of plan assets at beginning of year	$	102,800		$	92,219		$	—		$	—
Actual return on plan assets	1,654			6,591			—			—
Employer contributions	6,352			7,416			(1,200		)	(1,170		)
Benefit payments and adjustments	(4,206		)	(3,426		)	1,200			1,170
Fair value of plan assets at end of year	$	106,600		$	102,800		$	—		$	—
Funded status at end of year	$	(53,790	)	$	(54,800	)	$	(72,175	)	$	(74,552	)

(1) For the pension plan, the benefit obligation is the projected benefit obligation. For the postretirement benefit plan, the benefit obligation is the accumulated postretirement benefit obligation.

Schedule of Amounts Recognized in AOCI

The following table displays the effect that the unrecognized prior service cost and unrecognized actuarial loss of our plans had on accumulated other comprehensive income ("AOCI"), as reported in the accompanying Consolidated Balance Sheets:

	Pension Benefits				Postretirement Benefits
Years Ended December 31	2015		2014		2015		2014
Amounts recognized in AOCI
Unrecognized prior service cost	$	—	$	—	$	—	$	—
Unrecognized actuarial loss	52,936		56,943		20,806		32,979
Total amounts recognized in AOCI	$	52,936	$	56,943	$	20,806	$	32,979

Components of Net Periodic Benefit Cost

The components of the net periodic benefit cost for our pension and postretirement benefit plans are as follows:

	Pension Plan									Postretirement Benefit Plan
Years Ended December 31,	2015			2014			2013			2015		2014		2013
Net periodic benefit cost
Service cost	$	6,675		$	5,210		$	6,300		$	5,220	$	3,696	$	3,875
Interest cost	5,999			5,874			5,175			2,856		2,342		1,759
Expected return on plan assets	(7,800		)	(6,956		)	(5,772		)	—		—		—
Amortization of net loss	4,546			2,174			4,989			2,920		898		879
Net periodic benefit cost	$	9,420		$	6,302		$	10,692		$	10,996	$	6,936	$	6,513

Summary of Expected Benefit Payments

The following table summarizes the expected benefits to be paid from our plans over the next 10 years:

	2016		2017		2018		2019		2020		2021 - 2025
Pension benefits	$	4,680	$	5,060	$	5,420	$	5,930	$	6,500	$	43,200
Postretirement benefits	$	1,140	$	1,340	$	1,560	$	1,810	$	2,080	$	15,170