Share-Based Compensation Tables (Tables)

12 Months Ended

Dec. 31, 2021

Dec. 31, 2020

Share-based Payment Arrangement, Noncash Expense [Abstract]

Schedule Of Share-based Compensation Costs Related To Unvested Restricted Stock [Table Text Block]

The remaining share-based compensation cost, net related to our unvested restricted shares outstanding as of December 31, 2021 is approximately $60.8 million. The following table summarizes our expected share-based compensation cost, net related to our unvested restricted shares, in thousands:

	2022		2023		2024		Thereafter
Expected share-based compensation costs, net	$	25.1	$	18.3	$	10.2	$	7.2

Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block]

The following table summarizes our restricted stock activity for the years ended December 31, 2021, 2020 and 2019:

	Number of Shares	Weighted Average Grant Date Fair Value
Unvested restricted shares at January 1, 2019	871,117	$	72.65
Granted	190,020	$	107.50
Vested	(237,406)	$	64.46
Forfeited	(10,690)	$	79.58
Unvested restricted shares at December 31, 2019	813,041	$	83.10
Granted	261,731	$	144.89
Vested	(258,280)	$	73.47
Forfeited	(5,678)	$	111.04
Unvested restricted shares at December 31, 2020	810,814	$	105.92
Granted	290,607	$	131.84
Vested	(305,747)	$	91.06
Forfeited	(7,654)	$	113.02
Unvested restricted shares at December 31, 2021	788,020	$	121.18

During the years ended December 31, 2021 and 2020, shares were granted as follows:

Grant Period	Type	Plan	Shares Granted		Grant Date Fair Value Per Share			Vesting Type	Vesting Anniversary	Percentage
2021	Key Employees	2015 Equity Incentive Plan	2,500		$	196.75	(1)	Time Based	20.0% annually over 5 years
2021	Key Employees	2015 Equity Incentive Plan	1,004		$	202.31	(1)	Time Based	25.0% annually over 4 years
2021	Executive Officers	2015 Equity Incentive Plan	11,488		$	196.39	(1)	Time Based	20.0% annually over 5 years
2021	Executive Officers	2015 Equity Incentive Plan	54,000		$	151.89	(1)	Time Based	20.0% annually over 5 years
2021	Executive Officers	2015 Equity Incentive Plan	81,000	(2)	$	94.32	(2)	Market Condition	3rd	100.0	%
2021	Executive Officers	2015 Equity Incentive Plan	15,000		$	151.89	(1)	Time Based	33.3% annually over 3 years
2021	Executive Officers	2015 Equity Incentive Plan	15,000	(3)	$	87.49	(3)	Market Condition	3rd	100.0	%
2021	Key Employees	2015 Equity Incentive Plan	28,856		$	151.89	(1)	Time Based	33.3% annually over 3 years
2021	Key Employees	2015 Equity Incentive Plan	61,550		$	143.28	(1)	Time Based	20.0% annually over 5 years
2021	Executive Officers	2015 Equity Incentive Plan	3,400		$	147.19	(1)	Time Based	20.0% annually over 5 years
2021	Executive Officers	2015 Equity Incentive Plan	5,100	(4)	$	96.41	(4)	Market Condition	3rd	100.0	%
2021	Directors	2004 Non-Employee Director Option Plan	1,509		$	147.19	(1)	Time Based	3rd	100.0	%
2021	Directors	2004 Non-Employee Director Option Plan	10,200		$	148.44	(1)	Time Based	3rd	100.0	%
2020	Key Employees	2015 Equity Incentive Plan	13,873		$	140.39	(1)	Time Based	20.0% annually over 5 years
2020	Executive Officers	2015 Equity Incentive Plan	69,368		$	137.63	(1)	Time Based	20.0% annually over 5 years
2020	Key Employees	2015 Equity Incentive Plan	1,500		$	143.20	(1)	Time Based	20.0% annually over 5 years
2020	Key Employees	2015 Equity Incentive Plan	51,790		$	162.42	(1)	Time Based	20.0% annually over 5 years
2020	Executive Officers	2015 Equity Incentive Plan	46,000		$	165.97	(1)	Time Based	20.0% annually over 5 years
2020	Executive Officers	2015 Equity Incentive Plan	69,000	(5)	$	125.47	(5)	Market Condition	3rd	100.0	%
2020	Directors	2004 Non-Employee Director Option Plan	10,200		$	147.97	(1)	Time Based	3rd	100.0	%

(1)The fair values of the grants were determined by using the average closing price of our common stock on the dates the shares were issued.

(2)Share-based compensation for restricted stock awards with market conditions is measured based on an estimate of shares expected to vest. We estimate the fair value of share-based compensation for restricted stock with market conditions using a Monte Carlo simulation. At the grant date our common stock price was $151.89. Based on the Monte Carlo simulation we expect 62.1 percent of the 81,000 shares to vest.

(3)Share-based compensation for restricted stock awards with market conditions is measured based on an estimate of shares expected to vest. We estimate the fair value of share-based compensation for restricted stock with market conditions using a Monte Carlo simulation. At the grant date our common stock price was $151.89. Based on the Monte Carlo simulation we expect 57.6 percent of the 15,000 shares to vest.

(4)Share-based compensation for restricted stock awards with market conditions is measured based on an estimate of shares expected to vest. We estimate the fair value of share-based compensation for restricted stock with market conditions using a Monte Carlo simulation. At the grant date our common stock price was $147.19. Based on the Monte Carlo simulation we expect 65.5 percent of the 5,100 shares to vest.

(5)Share-based compensation for restricted stock awards with market conditions is measured based on an estimate of shares expected to vest. We estimate the fair value of share-based compensation for restricted stock with market conditions using a Monte Carlo simulation. At the grant date our common stock price was $165.97. Based on the Monte Carlo simulation we expect 75.6 percent of the 69,000 shares to vest.