Share-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2022

Share-Based Payment Arrangement [Abstract]

Summary of Total Compensation Cost Recognized for Share-Based Awards

Total compensation cost recognized for share-based awards was as follows for the years ended December 31, 2022, 2021, and 2020 (in thousands):

	2022		2021		2020
Share-based compensation expense (1)	$	7,463	$	7,360	$	8,295
Capitalized share-based compensation (2)		503		295		946
Total share-based compensation (3)	$	7,966	$	7,655	$	9,241

(1)Amounts are recorded in general and administrative expenses in our consolidated statements of operations.

(2)Amounts are recorded in building and improvements in our consolidated balance sheets.

(3)Amounts are recorded in additional paid-in capital and common noncontrolling interests in the AIR Operating Partnership in the AIR consolidated balance sheets, and in general partner and special limited partner and limited partners in the AIR Operating Partnership consolidated balance sheets.

Assumptions Used in Determination of Grant-Date Fair Value of Awards

The valuation assumptions for the 2022, 2021, and 2020 grants were as follows:

	2022	2021	2020
Grant date market value of a common share	$53.91	$36.84	$53.26
Risk-free interest rate	1.20% - 1.68%	0.24% - 0.78%	1.48% - 1.58%
Dividend yield	3.50%	4.00%	2.93%
Expected volatility	22.63% - 24.83%	23.08% - 28.21%	15.82% - 16.84%
Derived vesting period of TSR Restricted Stock and TSR LTIP I units	3.5 years	3.2 years	3.5 years
Weighted average expected term of TSR Stock Options and LTIP II units	5.4 years	5.4 years	5.9 years