SHAREHOLDERS' EQUITY - Compensation costs (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Stock-based compensation plans
Stock-based compensation expense	$ 10,097	$ 7,533	$ 6,836
Restricted stock
Stock-based compensation plans
Stock-based compensation expense	5,478	4,597	4,013
Performance shares
Stock-based compensation plans
Stock-based compensation expense	$ 4,619	$ 2,936	$ 2,823

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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