Compensation Related Costs, Share Based Payments (Tables)

12 Months Ended

Dec. 31, 2023

Share-Based Payment Arrangement [Abstract]

Share-Based Payment Arrangement, Restricted Stock and Restricted Stock Unit, Activity

The following tables set forth activity and various statistics for restricted stock unit awards outstanding under the respective plans for the period indicated:

	Number of Units	Weighted- Average Grant Date Fair Value
Nonvested at December 31, 2022	116,633	$	79.32
Granted	48,841	$	81.79
Vested	(31,328)	$	90.94
Forfeited	(7,198)	$	77.65
Nonvested at December 31, 2023	126,948	$	77.50

	2023		2022		2021
Weighted-average grant date fair value (per share)	$	81.79	$	76.96	$	72.69
Fair value of shares granted (thousands of dollars)	$	3,995	$	4,342	$	3,660

Schedule of Nonvested Performance-Based Units Activity

The following tables set forth activity and various statistics related to our performance stock unit awards and the assumptions used by us in the valuations of the 2023, 2022 and 2021 grants at the grant date:

	Number of Units	Weighted- Average Grant Date Fair Value
Nonvested at December 31, 2022	214,537	$	92.47
Granted	95,474	$	105.74
Vested	(50,188)	$	102.77
Forfeited	(12,497)	$	97.91
Nonvested at December 31, 2023	247,326	$	95.23

	2023	2022	2021
Volatility (a)	29.20%	34.00%	32.70%
Dividend yield	3.18%	3.22%	3.19%
Risk-free interest rate (b)	4.37%	1.65%	0.20%

(a) - Volatility based on historical volatility over three years using daily stock price observations of our peer utilities.

(b) - Using 3-year treasury rate.

	2023		2022		2021
Weighted-average grant date fair value (per share)	$	105.74	$	95.80	$	82.51
Fair value of shares granted (thousands of dollars)	$	10,095	$	8,360	$	8,860