Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2020

Share-based Payment Arrangement [Abstract]

Stock Based Compensation Expense

The following table discloses the amount of stock-based compensation expense:

	Year Ended December 31,
	2020		2019		2018
Restricted stock units	$	3,729	$	2,836	$	3,196
Performance stock units	2,324		1,526		672
Total stock-based compensation	$	6,053	$	4,362	$	3,868

Summarized Information for the Plans

Summarized information for the outstanding stock options follows:

	Number of Shares	Weighted Average Exercise Price (per share)		Aggregate Intrinsic Value (thousands)
Outstanding at December 31, 2019	238,748	$	23.30
Exercised	(117,324)	22.48
Expired	(1,508)	23.96
Outstanding and Exercisable at December 31, 2020	119,916	$	24.08	$	1,969

	Year Ended December 31,
	2020	2019	2018
Aggregate intrinsic value of options exercised (thousands)	1,392	425	298

Segregated Disclosure of Options Outstanding

Segregated disclosure of options outstanding at December 31, 2020 was as follows:

	Range of Exercise Prices
	Less than or equal to $15.63		Greater than $15.63
Options outstanding	5,965		113,951
Weighted average exercise price	$	15.63	$	24.53
Remaining contractual life	1.1		2.8
Options exercisable	5,965		113,951
Weighted average exercise price	$	15.63	$	24.53

Details of Nonvested Restricted Stock Units Activity

The following table provides details of the Company's restricted stock units for 2020:

	Number of Restricted Units	Weighted Average Grant-Date Fair Value (per share)		Aggregate Intrinsic Value (thousands)
Nonvested at December 31, 2019	230,962	$	33.49
Granted	158,256	28.58
Vested	(88,672)	35.04
Canceled	(49,720)	30.02
Accrued dividend equivalents	4,376	30.62
Nonvested at December 31, 2020	255,202	$	30.86
Vested but not released	1,508	18.04
Outstanding at December 31, 2020	256,710	$	30.78	$	7,902
Weighted-average remaining contractual term of shares outstanding (months)	20

	Year Ended December 31,
	2020		2019		2018
Weighted average grant-date fair value of restricted shares granted (per share)	$	28.58	$	32.52	$	34.53
Weighted average grant-date fair value of shares vested (thousands)	$	3,107	$	3,336	$	3,000

Performance Based Units Earned under Long-Term Incentive Plan

The following table provides details of the nonvested performance stock units earned under the Company’s Long-Term Incentive Plan:

	Number of Performance  Units	Weighted Average Grant- Date Fair Value (per share)		Aggregate Intrinsic Value (thousands)
Nonvested at December 31, 2019	59,335	$	33.79
Earned	92,816	27.35
Vested	(51,147)	31.50
Canceled	(20,064)	29.33
Accrued dividend equivalents	1,014	33.85
Nonvested at December 31, 2020	81,954	$	29.02
Vested but not released	49,376	31.39
Outstanding at December 31, 2020	131,330	$	29.91	$	3,928
Weighted-average remaining contractual term of performance stock units outstanding (months)	11

	Year Ended December 31,
	2020		2019		2018
Weighted average grant-date fair value of performance stock units granted (per share)	$	27.35	$	33.27	$	36.08
Weighted average grant-date fair value of performance stock units vested (thousands)	$	1,611	$	1,073	$	1,821