At September 30, 2021, we had five active stock-based compensation plans: the Non-Employee Directors’ Stock Retirement Plan (“Directors’ Plan”), the 2004 Omnibus Long-Term Incentive Plan (“2004 Plan”), the 2009 Omnibus Equity and Performance Incentive Plan (“2009 Plan”), the 2014 Performance and Incentive Compensation Plan (“2014 Plan”), and the 2018 Equity and Incentive Compensation Plan ("2018 Plan"). Future grants can only be made under the 2018 Plan.

These plans allow for grants of stock options, stock appreciation rights, restricted stock, restricted stock units ("RSUs"), performance shares, performance units, and other stock awards subject to the terms of the specific plans under which the awards are granted.

The following table summarizes the compensation expense included in selling, general and administrative expenses in the Condensed Consolidated Statements of (Loss) Earnings related to stock-based compensation plans:

	Three months ended				Nine months ended
	September 30,		September 30,		September 30,		September 30,
	2021		2020		2021		2020
Service-based RSUs	$	588	$	580	$	2,013	$	1,939
Performance-based RSUs		383		472		1,942		123
Cash-settled RSUs		16		67		151		102
Total	$	987	$	1,119	$	4,106	$	2,164
Income tax benefit		227		257		945		497
Net expense	$	760	$	862	$	3,161	$	1,667

The following table summarizes the unrecognized compensation expense related to non-vested RSUs by type and the weighted-average period in which the expense is to be recognized:

	Unrecognized
	Compensation		Weighted-
	Expense at		Average
	September 30, 2021		Period (years)
Service-based RSUs	$	1,818		1.38
Performance-based RSUs		2,988		1.80
Total	$	4,806		1.64

We recognize expense on a straight-line basis over the requisite service period for each separately vesting portion of the award as if the award was, in substance, multiple awards.

The following table summarizes the status of these plans as of September 30, 2021:

	2018 Plan		2014 Plan		2009 Plan		2004 Plan		Directors' Plan
Awards originally available		2,500,000		1,500,000		3,400,000		6,500,000	N/A
Maximum potential RSU and cash settled awards outstanding		611,278		35,100		45,200		14,545		4,722
Maximum potential awards outstanding		611,278		35,100		45,200		14,545		4,722
RSUs and cash settled awards vested and released		117,633		—		—		—		—
Awards available for grant		1,771,089		—		—		—		—

The following table summarizes the service-based RSU activity for the nine months ended September 30, 2021:

	Units			Weighted Average Grant Date Fair Value
Outstanding at December 31, 2020		367,428		$	21.28
Granted		68,065			32.93
Vested and released		(151,946	)		20.91
Forfeited		(15,506	)		29.17
Outstanding at September 30, 2021		268,041		$	24.00
Releasable at September 30, 2021		116,933		$	15.86

The following table summarizes the performance and market-based RSU activity for the nine months ended September 30, 2021:

	Units			Weighted Average Grant Date Fair Value
Outstanding at December 31, 2020		225,559		$	28.97
Granted		83,237			34.44
Attained by performance		18,107			28.33
Released		(53,137	)		28.33
Forfeited		(43,099	)		27.71
Outstanding at September 30, 2021		230,667		$	31.28
Releasable at September 30, 2021		196,748		$	32.62

Cash-Settled RSUs entitle the holder to receive the cash equivalent of one share of common stock for each unit when the unit vests. These RSUs are issued to key employees residing in foreign locations as direct compensation. Generally, these RSUs vest over a three-year period. Cash-Settled RSUs are classified as liabilities and are remeasured at each reporting date until settled. At September 30, 2021 and December 31, 2020 we had 32,085 and 30,009 cash-settled RSUs outstanding, respectively. At September 30, 2021 and December 31, 2020, liabilities of $276 and $396, respectively, were included in accrued expenses and other liabilities on our Condensed Consolidated Balance Sheets.