On April 4, 2018, the Board approved the 2018 Omnibus Incentive Plan (the “2018 Omnibus Plan”), which was subsequently approved by the stockholders and became effective on May 31, 2018 (the “Effective Date”). The 2018 Omnibus Plan replaced the previous 2010 Omnibus Incentive Plan (the “Prior Plan”). The 2018 Omnibus Plan was amended on May 28, 2020 to increase the number of shares available for issuance.

On June 1, 2023, the Company’s stockholders approved an amendment and restatement of the 2018 Omnibus Plan (the “2018 A&R Omnibus Plan”) which further increased the number of shares available for issuance, incorporated compensation recovery provisions consistent with new SEC and NASDAQ requirements and made certain other clarifying changes.

The A&R 2018 Omnibus Plan, as amended, allows the Company to grant up to 2,050,000 shares using stock options, stock appreciation rights, restricted stock, RSUs, performance units and PSAs, cash-based awards, and other stock-based awards to all key officers, key employees, and non-employee directors of the Company. Outstanding shares granted under the Prior Plan, totaling 2,631, as of December 31, 2023, remain subject to its terms and conditions, and additional awards from the Prior Plan are prohibited after the Effective Date. As of December 31, 2023, the Company had approximately 1,119,446 shares available for grant under the A&R 2018 Omnibus Plan. CSRSUs have no impact on the shares available for grant under the A&R 2018 Omnibus Plan, nor on the calculated shares used in earnings per share (“EPS”) calculations.

Stock-based compensation expense is included as part of direct costs and indirect and selling expenses on the consolidated statements of comprehensive income. The total stock-based compensation expense for the years ended December 31, 2023, 2022, and 2021, the unrecognized compensation expense at December 31, 2023, and the weighted-average period to recognize the remaining unrecognized shares are as follows:


	Stock-Based Compensation Expense
	Recognized as of December 31,						Unrecognized as of December 31,
	2023		2022		2021		2023		Weighted Average Period to Recognize (years)
Restricted Stock Units	$	9,413	$	9,300	$	8,563	$	13,517		1.7
Cash-Settled Restricted Stock Units		8,061		5,709		8,251		11,558		1.7
Non-Employee Director Awards		1,029		1,087		937		481		0.4
Performance Shares		4,416		2,784		3,731		4,351		1.5
Total	$	22,919	$	18,880	$	21,482	$	29,907

The assumptions of employment termination forfeiture rates used in the determination of fair value of stock awards during the 2023 calendar year were based on the Company’s historical average of actual forfeitures from the previous 10 years preceding the reporting period. The expected annualized forfeiture rates used during the 2023 calendar year varied from 0% to 21.59%.

Stock options are granted with an exercise price equal to the market value of the Company’s common stock on the date of grant. There were no stock options granted during 2023, 2022, and 2021.

The following table summarizes the changes in outstanding stock options:


	Number of Shares			Weighted Average Exercise Price		Aggregate Intrinsic Value
Outstanding at January 1, 2021		38,227		$	31.93
Exercised		(8,535	)	$	27.17
Granted		—		$	—
Forfeited/Expired		—		$	—
Outstanding at December 31, 2021		29,692		$	33.30
Exercised		(18,807	)	$	32.04
Granted		—		$	—
Forfeited/Expired		—		$	—
Outstanding at December 31, 2022		10,885		$	35.49
Exercised		(8,254	)	$	33.84
Granted		—		$	—
Forfeited/Expired		—		$	—
Outstanding at December 31, 2023		2,631		$	40.68	$	246
Vested plus expected to vest at December 31, 2023		2,631		$	40.68	$	246
Exercisable at December 31, 2023		2,631		$	40.68	$	246

The aggregate intrinsic value is based on the Company’s closing stock price of $134.09 as of December 31, 2023. The total intrinsic value of options exercised was $0.9 million, $1.9 million, and $0.8 million for the years ended December 31, 2023, 2022, and 2021, respectively. All options have vested as of December 31, 2023, and the weighted-average remaining contractual term for options vested and exercisable was 0.2 years.

Information regarding stock options outstanding as of December 31, 2023 is summarized below:


	OPTIONS OUTSTANDING						OPTIONS EXERCISABLE
Range of Exercise Prices	Number Outstanding As of December 31, 2023		Weighted Average Remaining Contractual Term		Weighted Average Exercise Price		Number Exercisable As of December 31, 2023		Weighted Average Exercise Price
$40.68 to $40.68		2,631		0.2	$	40.68		2,631	$	40.68

RSUs generally have a vesting term of three years. On vesting the employee is issued one share of stock for each RSU awarded. The fair value of shares vested was $7.3 million, $10.8 million, and $7.9 million for the years ended December 31, 2023, 2022, and 2021, respectively.

A summary of the Company’s RSUs is presented below.


	Number of Shares			Weighted- Average Grant Date Fair Value		Aggregate Intrinsic Value
Non-vested RSUs at January 1, 2021		305,399		$	66.51
Granted		132,757		$	95.68
Vested		(119,203	)	$	66.46
Cancelled		(15,117	)	$	68.53
Non-vested RSUs at December 31, 2021		303,836		$	79.17
Granted		148,361		$	93.70
Vested		(140,666	)	$	76.53
Cancelled		(26,705	)	$	77.16
Non-vested RSUs at December 31, 2022		284,826		$	88.23
Granted		89,388		$	110.80
Vested		(93,881	)	$	78.05
Cancelled		(21,815	)	$	94.01
Non-vested RSUs at December 31, 2023		258,518		$	99.25	$	34,665
RSUs expected to vest in the future		230,953		$	98.82	$	30,968

The aggregate intrinsic value in the preceding table is based on the Company’s closing stock price of $134.09 per share as of December 31, 2023.

CSRSUs generally have a vesting term of three years. The fair value of CSRSUs vested and settled in cash for the years ended December 31, 2023, 2022, and 2021 was $7.9 million, $6.6 million and $8.7 million, respectively. A summary of the Company’s CSRSUs is presented below.


	Number of Shares			Weighted- Average Grant Date Fair Value		Aggregate Intrinsic Value
Non-vested CSRSUs at January 1, 2021		241,481		$	65.06
Granted		52,246		$	89.51
Vested		(104,272	)	$	63.96
Cancelled		(23,195	)	$	69.68
Non-vested CSRSUs at December 31, 2021		166,260		$	72.79
Granted		115,024		$	97.88
Vested		(75,566	)	$	73.20
Cancelled		(17,299	)	$	80.02
Non-vested CSRSUs at December 31, 2022		188,419		$	87.28
Granted		70,742		$	110.65
Vested		(81,537	)	$	76.26
Cancelled		(19,040	)	$	91.94
Non-vested CSRSUs at December 31, 2023		158,584		$	102.82	$	21,264
CSRSUs expected to vest in the future		134,808		$	102.31	$	18,076

The aggregate intrinsic value in the preceding table is based on the Company’s closing stock price of $134.09 per share as of December 31, 2023.

The Company grants awards of registered shares to its non-employee directors on an annual basis under the A&R Omnibus Plan. A summary of the non-employee director awards is presented below:


	Number of Shares			Weighted- Average Grant Date Fair Value		Aggregate Intrinsic Value
Non-vested RSUs at January 1, 2021		6,510		$	64.47
Granted		11,186		$	90.73
Vested		(12,110	)	$	76.61
Cancelled		—		$	—
Non-vested RSUs at December 31, 2021		5,586		$	90.73
Granted		11,399		$	95.35
Vested		(11,637	)	$	93.39
Cancelled		—		$	—
Non-vested RSUs at December 31, 2022		5,348		$	94.79
Granted		8,211		$	127.81
Vested		(9,457	)	$	109.14
Cancelled		—		$	—
Non-vested RSUs at December 31, 2023		4,102		$	127.81	$	550
RSUs expected to vest in the future		4,102		$	127.81	$	550

The aggregate intrinsic value in the preceding table is based on the Company’s closing stock price of $134.09 per share as of December 31, 2023.

In 2015, the Board approved a performance-based share program (the “Program”) that provides for the issuance of PSAs to its senior management. Under the Program, the number of PSAs that the participant will receive depends on the Company’s achievement of two performance goals during two performance periods. The performance goals under the Program are based on (i) the Company’s compounded annual growth rate in EPS (adjusted to exclude certain items specified in the award's Agreement) during a two-year performance period (the “Initial Period”) and (ii) the Company’s cumulative total shareholder return relative to its peer group (“rTSR”) during a performance period from the first day of the performance period (typically January 1 of the year awarded) to the last day of the third year of the performance period (typically December 31). The PSAs will only be eligible to vest following the expiration of the three-year performance period. The actual shares vested will be subject to both continued employment by the Company (barring certain exceptions allowing for partial performance periods) and actual financial measures achieved. The final number of shares of common stock that will be issued to each participant at the end of the applicable performance period will be determined by multiplying the award by the product of two percentages: the first based on the Company’s EPS performance and the second based on the Company’s rTSR performance, subject to a minimum and maximum performance level. As of December 31, 2023, shares granted during 2021, 2022, and 2023 are within year three, two, and one of the performance periods, respectively, and therefore have not fully vested. A total of 45,141 shares granted in 2020 vested during 2023 after meeting the performance goals. As of December 31, 2023, a total of 69,650 shares granted in 2021 and 2022 are expected to vest in the future based on estimated financial measures achieved in the Initial Period and rTSR performance.

A summary of the Company’s PSAs is presented below.


	Number of Shares			Weighted- Average Grant Date Fair Value		Aggregate Intrinsic Value
Non-vested PSAs at January 1, 2021		142,121		$	68.19
Granted		54,216		$	85.03
Vested		(63,258	)	$	65.05
Cancelled		—		$	—
Non-vested PSAs at December 31, 2021		133,079		$	76.54
Granted		38,412		$	93.15
Vested		(47,634	)	$	82.38
Cancelled		(3,170	)	$	80.64
Non-vested PSAs at December 31, 2022		120,687		$	79.42
Granted		36,956		$	115.67
Vested		(45,141	)	$	58.76
Cancelled		(6,934	)	$	61.49
Non-vested PSAs at December 31, 2023		105,568		$	102.12	$	14,156
PSAs expected to vest in the future		69,650		$	104.95	$	9,339

The aggregate intrinsic value in the preceding table is based on the Company’s closing stock price of $134.09 per share as of December 31, 2023.

The fair value of the awards is estimated on the grant date using a Monte Carlo simulation model due to the market condition for the rTSR component. The fair value assumptions using the Monte Carlo simulation model for awards granted in 2023, 2022, and 2021 were:


	2023			2022			2021
Dividend Yield		0.5	%		0.6	%		0.6	%
Historical Volatility		33.6	%		39.0	%		40.9	%
Risk-Free Rate of Returns		3.8	%		2.1	%		0.3	%