Stock-Based Compensation

9 Months Ended

Sep. 30, 2021

Share-based Payment Arrangement [Abstract]

A combined summary of activity in our active stock plans is presented in the table. Performance stock units outstanding are presented assuming attainment of the maximum payout rate as set forth by the performance criteria. As of September 30, 2021, there were 917,440 shares remaining available for grant for future stock-based compensation awards.


	Director Deferred Stock Units Outstanding			Non-Vested Stock Awards/Stock Units Outstanding			Performance Stock Units Outstanding			Stock Options Outstanding
	Number of Units	Weighted- Average Fair Value at Grant		Number of Shares/Units	Weighted- Average Fair Value at Grant		Number of Units	Weighted- Average Fair Value at Grant		Number of Shares	Weighted- Average Exercise Price
Balance, January 1, 2021	52,860	$	75.47	470,359	$	86.24	201,257	$	77.18	1,739,559	$	66.11
Authorized	—	—		—	—		—	—		—	—
Granted	5,940	117.90		—	—		—	—		—	—
Exercised/vested	(2,499)	92.03		(1,213)	98.90		(35,131)	92.27		(611,201)	61.86
Forfeited/expired	—	—		(26,439)	87.08		(9,752)	75.70		—	—
Balance, September 30, 2021	56,301	$	79.21	442,707	$	86.16	156,374	$	73.88	1,128,358	$	68.41

Shares issued in connection with stock compensation awards are issued from available treasury shares. If no treasury shares are available, new shares are issued from available authorized shares. Shares issued in connection with stock compensation awards along with other related information were as follows:


	Three Months Ended September 30,				Nine Months Ended September 30,
	2021		2020		2021		2020
New shares issued from available authorized shares	—		—		—		—
Shares issued from available treasury stock	21,968		53,425		650,044		196,948
Total	21,968		53,425		650,044		196,948

Proceeds from stock option exercises	$	1,128	$	2,698	$	37,810	$	7,544

Stock-based compensation expense is recognized ratably over the requisite service period for all awards. For most stock option awards, the service period generally matches the vesting period. For stock options granted to certain executive officers and for non-vested stock units granted to all participants, the service period does not extend past the date the participant reaches 65 years of age. Deferred stock units granted to non-employee directors generally have immediate vesting and the related expense is fully recognized on the date of grant. For performance stock units, the service period generally matches the three-year performance period specified by the award, however, the service period does not extend past the date the participant reaches 65 years of age. Expense recognized each period is dependent upon our estimate of the number of shares that will ultimately be issued.

Stock-based compensation expense and the related income tax benefit is presented in the following table.


	Three Months Ended September 30,				Nine Months Ended September 30,
	2021		2020		2021		2020

Non-vested stock awards/stock units	$	1,559	$	1,999	$	5,210	$	6,325
Director deferred stock units	—		—		700		770
Performance stock units	426		444		1,846		1,132
Total	$	1,985	$	2,443	$	7,756	$	8,227
Income tax benefit	$	281	$	450	$	1,162	$	1,539

Unrecognized stock-based compensation expense at September 30, 2021 is presented in the table below. Unrecognized stock-based compensation expense related to performance stock units is presented assuming attainment of the maximum payout rate as set forth by the performance criteria.


Non-vested stock awards/stock units	$	10,918
Performance stock units	4,450
Total	$	15,368