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SIGNIFICANT ACCOUNTING POLICIES - Stock-Based Compensation (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award
Options granted (in shares)			0	0
Stock option
Share-based Compensation Arrangement by Share-based Payment Award
Vesting period (in years)			3 years
Options granted (in shares)	0	0
Stock option \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award
Vesting period (in years)			3 years
Restricted stock
Share-based Compensation Arrangement by Share-based Payment Award
Vesting period (in years)			3 years
Restricted stock \| Vesting period one
Share-based Compensation Arrangement by Share-based Payment Award
Vesting period (in years)			6 years
Restricted stock \| Vesting period two
Share-based Compensation Arrangement by Share-based Payment Award
Vesting period (in years)			6 months
2007 Plan
Share-based Compensation Arrangement by Share-based Payment Award
Shares available for award (in shares)					1,585,000
2017 Plan
Share-based Compensation Arrangement by Share-based Payment Award
Shares available for award (in shares)	1,789,647		1,789,647