EMPLOYEE BENEFITS (Tables)

12 Months Ended

Dec. 31, 2018

Employee Benefits Including Defined Benefit Plans and Share-based Compensation Plans [Abstract]

Schedule of changes in projected benefit obligation and fair value of plan assets



	Year Ended December 31,
	2018									2017									2016
	Defined Benefit Pension Plan			Defined Benefit Pension Plan Acquired			Restoration Plan			Defined Benefit Pension Plan			Defined Benefit Pension Plan Acquired			Restoration Plan			Defined Benefit Pension Plan			Defined Benefit Pension Plan Acquired			Restoration Plan
	(in thousands)
Change in Projected Benefit Obligation:
Benefit obligation at end of prior year	$	94,276		$	4,392		$	14,642		$	88,071		$	4,238		$	12,723		$	80,040		$	4,685		$	12,024
Service cost	1,548			—			293			1,398			—			247			1,375			—			207
Interest cost	3,392			163			597			3,601			177			567			3,731			212			535
Actuarial (gain) loss	(9,399		)	(480		)	344			5,404			418			1,751			4,978			275			237
Benefits paid	(3,622		)	(183		)	(576		)	(4,128		)	(43		)	(646		)	(3,632		)	(31		)	(280		)
Expenses paid	(203		)	(19		)	—			(70		)	(47		)	—			(91		)	(39		)	—
Plan amendments	—			—			—			—			—			—			121			—			—
Settlements	—			—			—			—			(351		)	—			—			(864		)	—
Special and contractual termination benefits	—			—			—			—			—			—			1,549			—			—
Benefit obligation at end of year	85,992			3,873			15,300			94,276			4,392			14,642			88,071			4,238			12,723
Change in Plan Assets:
Fair value of plan assets at end of prior year	91,233			4,031			—			85,293			2,993			—			76,355			3,740			—
Actual return	(4,497		)	(259		)	—			8,138			479			—			7,661			187			—
Employer contributions	2,000			500			576			2,000			1,000			646			5,000			—			280
Benefits paid	(3,622		)	(183		)	(576		)	(4,128		)	(43		)	(646		)	(3,632		)	(31		)	(280		)
Expenses paid	(203		)	(19		)	—			(70		)	(47		)	—			(91		)	(39		)	—
Settlements	—			—			—			—			(351		)	—			—			(864		)	—
Fair value of plan assets at end of year	84,911			4,070			—			91,233			4,031			—			85,293			2,993			—
(Un)Funded status at end of year	(1,081		)	197			(15,300		)	(3,043		)	(361		)	(14,642		)	(2,778		)	(1,245		)	(12,723		)
Accrued benefit (liability) asset recognized	$	(1,081	)	$	197		$	(15,300	)	$	(3,043	)	$	(361	)	$	(14,642	)	$	(2,778	)	$	(1,245	)	$	(12,723	)
Accumulated benefit obligation at end of year	$	77,888		$	3,873		$	13,403		$	83,802		$	4,392		$	13,246		$	77,639		$	4,238		$	11,133

Schedule of amounts recognized in other comprehensive income (loss)

Amounts related to our defined benefit pension plans and restoration plan recognized as a component of other comprehensive (loss) income were as follows (in thousands):



	Year Ended December 31,
	2018									2017									2016
	Defined Benefit Pension Plan			Defined Benefit Pension Plan Acquired			Restoration Plan			Defined Benefit Pension Plan			Defined Benefit Pension Plan Acquired			Restoration Plan			Defined Benefit Pension Plan			Defined Benefit Pension Plan Acquired			Restoration Plan
Recognition of net loss	$	1,512		$	—		$	677		$	1,312		$	—		$	301		$	1,642		$	—		$	186
Recognition of prior service (credit) cost	(14		)	—			7			(14		)	—			6			(14		)	—			6
Recognition of loss (gain) due to settlement	—			—			—			—			8			—			—			(8		)	—
Net (loss) gain occurring during the year	(1,581		)	(69		)	(344		)	(3,317		)	(150		)	(1,751		)	(2,541		)	(354		)	(237		)
Net prior service cost occurring during the year	—			—			—			—			—			—			(121		)	—			—
	(83		)	(69		)	340			(2,019		)	(142		)	(1,444		)	(1,034		)	(362		)	(45		)
Deferred tax benefit (expense)	17			14			(71		)	241			30			259			362			127			16
Other comprehensive (loss) income, net of tax	$	(66	)	$	(55	)	$	269		$	(1,778	)	$	(112	)	$	(1,185	)	$	(672	)	$	(235	)	$	(29	)

Schedule of amounts in accumulated other comprehensive income (loss) recognized in net periodic benefit cost during period

Net amounts recognized in net periodic benefit cost and other comprehensive loss were as follows (in thousands):



	December 31, 2018								December 31, 2017
	Defined Benefit Pension Plan			Defined Benefit Pension Plan Acquired		Restoration Plan			Defined Benefit Pension Plan			Defined Benefit Pension Plan Acquired			Restoration Plan
Net loss	$	1,512		$	—	$	677		$	1,312		$	—		$	301
Prior service (credit) cost	(14		)	—		7			(14		)	—			6
Loss (gain) recognized due to settlement	—			—		—			—			8			—
	1,498			—		684			1,298			8			307
Deferred tax (expense) benefit	(315		)	—		(144		)	(454		)	(2		)	(107		)
Accumulated other comprehensive income (loss), net of tax	$	1,183		$	—	$	540		$	844		$	6		$	200

Schedule of amounts recognized as a component of accumulated other comprehensive loss

Amounts recognized as a component of accumulated other comprehensive loss were as follows (in thousands):



	December 31, 2018									December 31, 2017
	Defined Benefit Pension Plan			Defined Benefit Pension Plan Acquired			Restoration Plan			Defined Benefit Pension Plan			Defined Benefit Pension Plan Acquired			Restoration Plan
Net (loss) gain	$	(28,928	)	$	(171	)	$	(3,984	)	$	(28,859	)	$	(102	)	$	(4,317	)
Prior service cost	(123		)	—			(24		)	(109		)	—			(31		)
	(29,051		)	(171		)	(4,008		)	(28,968		)	(102		)	(4,348		)
Deferred tax benefit (expense)	6,100			35			841			9,674			15			1,276
Reclassification of certain deferred tax effects ⁽¹⁾	—			—			—			(3,591		)	6			(364		)
Accumulated other comprehensive (loss) income, net of tax	$	(22,951	)	$	(136	)	$	(3,167	)	$	(22,885	)	$	(81	)	$	(3,436	)


(1)	Amounts reclassified to retained earnings due to early adoption of ASU 2018-02. See “Note 1 – Summary of Significant Accounting and Reporting Policies” for further information.

Schedule of components of net periodic pension cost and postretirement benefit cost

Net periodic pension cost and postretirement benefit cost included the following components (in thousands):



	Year Ended December 31,
	2018			2017			2016
Defined Benefit Pension Plan:
Service cost	$	1,548		$	1,398		$	1,375
Interest cost	3,392			3,601			3,731
Expected return on assets	(6,483		)	(6,050		)	(5,224		)
Net loss amortization	1,512			1,312			1,642
Prior service credit amortization	(14		)	(14		)	(14		)
Special and contractual termination benefits	—			—			1,549
Net periodic benefit cost	$	(45	)	$	247		$	3,059
Defined Benefit Pension Plan Acquired:
Service cost	$	—		$	—		$	—
Interest cost	163			177			212
Expected return on assets	(290		)	(212		)	(265		)
Net loss amortization	—			—			—
Prior service credit amortization	—			—			—
Loss (gain) recognized due to settlement	—			8			(8		)
Net periodic benefit cost	$	(127	)	$	(27	)	$	(61	)
Restoration Plan:
Service cost	$	293		$	247		$	207
Interest cost	597			567			535
Net loss amortization	677			301			186
Prior service cost amortization	7			6			6
Net periodic benefit cost	$	1,574		$	1,121		$	934

Schedule of amounts in accumulated other comprehensive income (loss) that is expected to be recognized as a component of net periodic benefit cost during the next fiscal year

The amounts in accumulated other comprehensive income (loss) that are expected to be recognized as components of net periodic benefit cost during 2019 are as follows (in thousands):



	Defined Benefit Pension Plan			Defined Benefit Pension Plan Acquired		Restoration Plan
Net loss	$	1,774		$	—	$	398
Prior service (credit) cost	(14		)	—		6
	1,760			—		404
Deferred tax benefit	(370		)	—		(85		)
Accumulated other comprehensive loss, net of tax	$	1,390		$	—	$	319

Schedule of assumptions used to determine benefit obligation and net periodic benefit cost

The assumptions used to determine the benefit obligation were as follows:



	December 31, 2018						December 31, 2017
	Defined Benefit Pension Plan		Defined Benefit Pension Plan Acquired		Restoration Plan		Defined Benefit Pension Plan		Defined Benefit Pension Plan Acquired		Restoration Plan
Discount rate	4.32	%	4.32	%	4.32	%	3.71	%	3.71	%	3.71	%
Compensation increase rate	3.50	%	—		3.50	%	3.50	%	—		3.50	%

The assumptions used to determine net periodic pension cost and postretirement benefit cost were as follows:



	Year Ended December 31,
	2018		2017		2016
Defined Benefit Pension Plan:
Discount rate	3.71	%	4.23	%	4.56	%
Expected long-term rate of return on plan assets	7.25	%	7.25	%	7.25	%
Compensation increase rate	3.50	%	3.50	%	3.50	%
Defined Benefit Pension Plan Acquired
Discount rate	3.71	%	4.23	%	4.56	%
Expected long-term rate of return on plan assets	7.25	%	7.25	%	7.25	%
Compensation increase rate	—		—		—
Restoration Plan:
Discount rate	3.71	%	4.23	%	4.56	%
Compensation increase rate	3.50	%	3.50	%	3.50	%

Schedule of allocation of plan assets

The major categories of assets in our Plan and the Acquired Plan are presented in the following table (in thousands). Assets are segregated by the level of the valuation inputs within the fair value hierarchy established by ASC Topic 820 “Fair Value Measurements and Disclosures,” utilized to measure fair value (see “Note 13 – Fair Value Measurement”). Our Restoration Plan is unfunded.



	December 31, 2018				December 31, 2017
	Defined Benefit Pension Plan		Defined Benefit Pension Plan Acquired		Defined Benefit Pension Plan		Defined Benefit Pension Plan Acquired
Level 1:
Cash	$	278	$	—	$	423	$	—
Equity Securities:
U.S. large cap ⁽¹⁾	5,204		—		6,198		—
U.S. mid cap ⁽²⁾	18,913		—		21,379		—
U.S. small cap⁽³⁾	9,900		—		10,706		—
Fixed Income Securities:
International developed⁽⁴⁾	6,733		—		8,601		—
International emerging⁽²⁾	3,464		—		4,308		—
Level 2:
Cash Equivalents	15,025		—		13,256		—
Equity Securities:
U.S. large cap ⁽¹⁾	—		1,360		—		1,440
U.S. mid cap ⁽²⁾	—		152		—		167
U.S. small cap ⁽³⁾	—		72		—		84
International ⁽⁵⁾	—		735		—		712
Fixed Income Securities:
Corporate bonds⁽⁶⁾	952		407		1,118		378
U.S. government agencies⁽⁶⁾	20,182		—		19,303		—
Municipal bonds⁽⁶⁾	3,991		—		5,595		—
U.S. agency mortgage-backed securities ⁽⁷⁾	269		—		346		—
Asset-backed securities ⁽⁸⁾	—		743		—		717
Real estate ⁽⁹⁾	—		286		—		241
Balanced Asset Allocation ⁽¹⁰⁾	—		84		—		81
Other ⁽¹¹⁾	—		231		—		211
Total fair value of plan assets	$	84,911	$	4,070	$	91,233	$	4,031


(1)	For the defined benefit pension plan, this category is comprised of individual securities that are actively managed and a broadly diversified “passive” mutual fund. The Acquired Plan assets in this category consist of pooled separate accounts invested in mutual funds and domestic stocks.


(2)	For the defined benefit pension plan, this category is comprised of broadly diversified “passive” mutual funds. The Acquired Plan assets in this category consist of pooled separate accounts invested in mutual funds and domestic stocks.


(3)	For the defined benefit pension plan, this category is comprised of broadly diversified “passive” mutual funds and shares of Southside Bancshares stock that is owned in the Plan. The Acquired Plan assets in this category consist of pooled separate accounts invested in mutual funds and domestic stocks.


(4)	This category is comprised of individual securities that are actively managed and a broadly diversified “passive” mutual fund.


(5)	This category is comprised of pooled separate accounts invested in mutual funds and international stocks.


(6)	For the defined benefit pension plan, this category is comprised of individual investment grade securities that are generally held to maturity in the Plan. The Acquired Plan assets in this category consist of pooled separate accounts invested in investment grade and below investment grade bonds.


(7)	This category is comprised of individual securities that are generally not held to maturity.


(8)	This category is mainly comprised of a pooled separate account invested in asset backed securities, residential mortgage backed securities, commercial mortgage backed securities and corporate bonds.


(9)	This category is comprised of a pooled separate account invested in commercial real estate and includes mortgage loans which are backed by the associated properties.


(10)	This category is comprised of a pooled separate account invested in a single mutual fund invested in a combination of fixed income and equity investment options.


(11)	This category is comprised of a pooled separate account invested in a broad range of instruments including, but not limited to, equities, bonds, currencies, convertible securities and derivatives such as futures, options, swaps and forwards.

Schedule of expected future benefit payments related to pension and postretirement plans

As of December 31, 2018, expected future benefit payments related to the Plan, the Acquired Plan and the Restoration Plan were as follows (in thousands):



	Defined Benefit Pension Plan		Defined Benefit Pension Plan Acquired		Restoration Plan
2019	$	3,836	$	66	$	723
2020	3,951		229		780
2021	4,142		129		916
2022	4,354		90		1,031
2023	4,520		92		1,005
2024 through 2028	25,008		897		5,521
	$	45,811	$	1,503	$	9,976

Schedule of shares issued in connection with stock compensation awards

Shares issued in connection with stock compensation awards along with other related information are presented in the following table without the retroactive recognition of stock dividends (in thousands, except share amounts):



	Year Ended December 31,
	2018		2017		2016
New shares issued from available authorized shares	—		48,311		108,225
New shares issued from available treasury shares	140,692		111,045		—
Total	140,692		159,356		108,225

Proceeds from stock option exercises	$	2,653	$	2,692	$	1,663

Schedule of stock option valuation assumptions

The estimated weighted-average grant-date fair value per option and the underlying Black-Scholes option-pricing model assumptions are summarized in the following table for years in which we granted NQSOs pursuant to the incentive plans:



	Years Ended December 31,
	2018	2017	2016
Weighted-average grant date fair value per option	$6.78	—	$7.18
Weighted-average assumptions:
Risk-free interest rates	2.81%	—	1.79%
Expected dividend yield	1.10%	—	2.69%
Expected volatility factors of the market price of Southside Bancshares common stock	25.41%	—	27.02%
Expected option life (in years)	6.2	—	6.2

Schedule of stock options and restricted stock units award activity

A combined summary of activity in our share-based plans as of December 31, 2018 is presented below:



	Restricted Stock Units Outstanding				Stock Options Outstanding
	Number of Shares		Weighted- Average Grant-Date Fair Value		Number of Shares		Weighted- Average Exercise Price		Weighted- Average Grant-Date Fair Value
Balance, January 1, 2018	78,253		$	32.04	690,312		$	26.02	$	6.19
Granted	64,358		34.28		356,849		34.52		6.78
Stock options exercised	—		—		(115,277	)	23.02		5.69
Stock awards vested	(29,752	)	31.14		—		—		—
Forfeited	(3,109	)	32.93		(16,980	)	32.51		6.67
Canceled/expired	—		—		(5,553	)	30.06		6.68
Balance, December 31, 2018	109,750		$	33.57	909,351		$	29.59	$	6.47

Schedule of shares stock option exercise price range

Other information regarding options outstanding and exercisable as of December 31, 2018 is as follows:



				Options Outstanding				Options Exercisable
Range of Exercise Prices				Number of Shares	Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Life in Years	Number of Shares	Weighted- Average Exercise Price
$	14.67	-	$20.00	110,291	$	15.89	3.03	110,291	$	15.89
20.01		-	25.00	106,826	22.92		5.43	82,747	23.01
25.01		-	30.00	202,009	26.68		6.47	136,613	26.58
30.01		-	35.00	346,965	34.52		9.41	—	—
35.01		-	37.28	143,260	37.28		7.90	76,710	37.28
Total				909,351	$	29.59	7.28	406,361	$	24.97