Stock-Based Compensation (Tables)

6 Months Ended

Jun. 30, 2023

Share-Based Payment Arrangement [Abstract]

Summary of Activity Under Stock Option Plan

The following table is a summary of the activity under both the Employee Plan and the Non-Employee Directors’ Plan:

						Wgtd. Avg.
				Wgtd. Avg.		Remaining	Aggregate
				Exercise		Contractual	Intrinsic
	Options			Price		Term	Value
	(Dollars in thousands, except option data)
Six Months Ended June 30, 2023
Outstanding at December 31, 2022		1,310,290		$	52.51
Exercised		(45,899	)		33.54
Canceled, forfeited, or expired		(8,500	)		87.97
Outstanding at June 30, 2023		1,255,891			52.96	10.18 Yrs.	$	49,029
Exercisable at June 30, 2023		477,266			31.74	6.41 Yrs.	$	28,760

Options Exercised Under Stock Option Plan

The following table has additional information regarding options exercised under both the Employee Plan and the Non-Employee Directors’ Plan:

	Three Months Ended June 30,				Six Months Ended June 30,
	2023		2022		2023		2022
	(Dollars in thousands)				(Dollars in thousands)
Total intrinsic value of options exercised	$	1,979	$	2,979	$	2,331	$	8,943
Cash received from options exercised		1,318		1,303		1,539		4,292
Tax benefit realized from options exercised		475		716		560		2,150

Assumptions Used for Computing Stock-Based Compensation Expense

The following table shows the assumptions used for computing stock-based compensation expense under the fair value method on options granted during the periods presented:

	Six Months Ended June 30,
	2023		2022
Weighted average grant-date fair value per share of options granted	$	—	$	29.08
Risk-free interest rate		—	1.75 to 3.25%
Dividend yield		—	2.00%
Stock price volatility		—	34.61 to 34.71%
Expected term		—	10 Yrs

Summary of Activity Under RSU Plan

The following table is a summary of the activity under the Company's RSU plan.

			Wgtd. Avg.
	Restricted		Grant Date
	Stock Units		Fair Value
Six Months Ended June 30, 2023
Nonvested at December 31, 2022		—
Granted		2,625	$	93.66
Nonvested at June 30, 2023		2,625

Summary of Accumulated Stock Units

A summary of the accumulated stock units is as follows:

	June 30,		December 31,
	2023		2022
Accumulated stock units		115,848		129,609
Average price	$	38.26	$	34.91

Stock-based Employee Compensation Expense

The components of stock-based compensation expense for all share-based compensation plans and related tax benefits are as follows:

	Three Months Ended June 30,				Six Months Ended June 30,
	2023		2022		2023		2022
	(Dollars in thousands)				(Dollars in thousands)
Stock-based compensation expense	$	831	$	460	$	1,213	$	918
Tax benefit		200		111		292		221
Stock-based compensation expense, net of tax	$	631	$	349	$	921	$	697

Unearned Stock-based Compensation Expense

The Company will continue to amortize the unearned stock-based compensation expense over the remaining vesting period of approximately seven years. The following table shows the unearned stock-based compensation expense:

	June 30, 2023
	(Dollars in thousands)
Unearned stock-based compensation expense	$	11,867