Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2023

Summary of Stock-Based Compensation Expense

The following table summarizes the Company’s stock-based compensation expense (in thousands):

	Year Ended December 31,
	2023		2022		2021
Time-based restricted stock and restricted stock units	$	3,897	$	3,783	$	2,892
Performance-based restricted stock and restricted stock units		4,836		540		4,681
Stock appreciation rights		908		792		485
Employee stock purchase plan		523		214		381
Total stock-based compensation	$	10,164	$	5,329	$	8,439

Summary of Assumptions Used to Estimate Fair Value of Each SAR

For SARs issued in the years ended December 31, 2023, December 31, 2022, and December 31, 2021, respectively, the assumptions shown in the following table were used:

	Year Ended December 31,
	2023			2022			2021
Dividend yield		0	%		0	%		0	%
Average risk-free interest rate		4.0	%		1.9	%		0.6	%
Expected term (years)		5			5			5
Expected volatility		49.5	%		44.9	%		58.7	%

SAR Activity

SAR activity under the Plan and all predecessor stock incentive plans is as follows:

	SARs			Weighted- Average Grant Price Per Share		Weighted- Average Remaining Contractual Life (Years)		Aggregate Intrinsic Value as of December 31, 2021
Outstanding at December 31, 2020		293,276		$	22.15
Granted		15,029		$	104.56
Exercised		(102,562	)	$	9.45
Canceled		(4,745	)	$	61.66
Outstanding at December 31, 2021		200,998		$	33.86
Granted		32,971		$	82.01
Exercised		—		$	—
Canceled		—		$	—
Outstanding at December 31, 2022		233,969		$	40.64
Granted		51,916		$	56.80
Exercised		(53,036	)	$	11.95
Canceled		(12,969	)	$	75.25
Outstanding at December 31, 2023		219,880		$	49.34		6.3	$	6,393,512
Vested at December 31, 2023		150,657		$	41.54		5.0	$	6,378,706
Exercisable at December 31, 2023		150,657		$	41.54		5.0	$	6,378,706

Time-Based Restricted Stock and Time-Based Restricted Stock Units [Member]

Restricted Stock Activity

Time-based restricted stock and restricted stock unit activity under the Plan and all predecessor stock incentive plans is as follows:

	Time-based Restricted Stock and Restricted Stock Unit			Weighted- Average Grant Price Per Share
Nonvested at December 31, 2020		160,722		$	35.68
Granted		33,703		$	100.50
Vested		(78,081	)	$	37.81
Forfeited		(4,798	)	$	66.00
Nonvested at December 31, 2021		111,546		$	52.91
Granted		57,094		$	75.06
Vested		(56,719	)	$	58.13
Forfeited		(1,286	)	$	86.84
Nonvested at December 31, 2022		110,635		$	61.28
Granted		97,177		$	58.50
Vested		(81,080	)	$	56.52
Forfeited		(10,228	)	$	66.19
Nonvested at December 31, 2023		116,504		$	65.00

Performance-Based Restricted Stock and Performance-Based Restricted Stock Units [Member]

Restricted Stock Activity

Performance-based restricted stock activity under the Plan is as follows:

	Performance-based Restricted Stock and Performance-based Restricted Stock Units			Weighted- Average Grant Price Per Share
Nonvested at December 31, 2020		72,570		$	43.42
Granted		36,522		$	86.26
Vested		(45,051	)	$	39.41
Forfeited		(6,273	)	$	65.30
Nonvested at December 31, 2021		57,768		$	71.21
Granted		72,152		$	76.14
Vested		(57,875	)	$	64.43
Forfeited		(562	)	$	82.95
Nonvested at December 31, 2022		71,483		$	81.57
Granted		96,103		$	56.79
Vested		(30,038	)	$	66.26
Forfeited		(28,163	)	$	74.39
Nonvested at December 31, 2023		109,385		$	65.92