Share-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2021

Share-based Payment Arrangement [Abstract]

Summary of Restricted Share and Restricted Stock Unit Activity

The following table presents the changes in Equity Commonwealth’s issued and outstanding common shares and units for the year ended December 31, 2021:

	Common Shares	OP Units and LTIP Units	Total
Outstanding at January 1, 2021	121,522,555	243,516	121,766,071
Repurchase and surrender of shares	(6,981,370)	—	(6,981,370)
Share-based compensation grants and vesting, net of forfeitures	664,633	3,701	668,334
Outstanding at December 31, 2021	115,205,818	247,217	115,453,035
Noncontrolling ownership interest in the Operating Trust			0.21	%

The table below presents a summary of restricted share, RSU and LTIP Unit activity for the years ended December 31, 2021, 2020 and 2019:

	Number of Restricted Shares and Time-Based LTIP Units	Weighted Average Grant Date Fair Value		Number of RSUs and Market-Based LTIP Units	Weighted Average Grant Date Fair Value
Outstanding at December 31, 2018	425,888	$	28.70	2,046,644	$	15.47
Granted	138,819	32.20		568,609	15.91
Vested	(164,074)	28.60		(384,811)	15.53
Not earned(1)	—	—		(225,654)	15.57
Forfeited	(319)	31.08		(1,613)	15.56
Outstanding at December 31, 2019	400,314	$	29.95	2,003,175	$	15.57
Granted	136,356	32.47		532,243	16.12
Vested	(149,103)	29.65		(473,369)	15.79
Not earned(1)	—	—		(97,131)	15.97
Forfeited(2)	(1,879)	31.41		—	—
Outstanding at December 31, 2020	385,688	$	31.52	1,964,918	$	15.65
Granted	144,672	28.06		619,750	15.19
Vested	(188,990)	30.99		(605,096)	15.31
Not earned(1)	—	—		—	—
Forfeited	—	—		—	—
Outstanding at December 31, 2021	341,370	$	30.35	1,979,572	$	15.61

(1) The table presents the maximum number of shares issued or issuable from outstanding equity awards. RSUs and market-based LTIP Units not earned are the shares market-based award recipients do not receive based on the performance measurement completed at the end of the performance period.

(2) Restricted shares forfeited as a result of a resignation of an independent Trustee in November 2020.

Summary of Assumptions and Fair Values for Restricted Stock Units Granted in the Period

The assumptions and fair values for the RSUs and market-based LTIP Units granted for the years ended December 31, 2021, 2020 and 2019 are included in the following table on a per share and unit basis.

	2021			2020			2019
Fair value of RSUs and market-based LTIP Units granted at the target amount	$	37.87		$	40.17		$	39.65
Fair value of RSUs and market-based LTIP Units granted at the maximum amount	$	15.19		$	16.12		$	15.91
Expected term (years)	4			4			4
Expected volatility	16.99		%	12.39		%	13.98		%
Expected dividend yield	—		%	—		%	—		%
Risk-free rate	0.17		%	1.41		%	2.52		%