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SHAREHOLDERS' EQUITY - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended		2 Months Ended	12 Months Ended
	Jan. 31, 2020	Jun. 30, 2016	Mar. 12, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Equity incentive plans
Dividends declared (in dollars per share)				$ 0.88	$ 0.84
Restricted Stock
Compensation expense				$ 1,821	$ 1,492
Restricted stock units
Restricted Stock
Compensation expense				140	$ 142
Restricted stock grants
Restricted Stock
Grants in period (in shares)	158,299				156,399
Compensation expense				1,681	$ 1,350
Unearned compensation				$ 4,411	$ 3,328
Shares granted but not yet vested (in shares)				744,145	725,296	705,847
Vesting period for shares issued				5 years
Remaining weighted average vesting period				2 years 1 month 6 days
Incentive Plan 2020
Equity incentive plans
Shares authorized for issuance (in shares)				1,000,000
Incentive Plan 2020 \| Restricted stock grants \| Subsequent Event
Restricted Stock
Grants in period (in shares)			156,774
Incentive Plan 2016
Equity incentive plans
Shares authorized for issuance (in shares)				600,000
Incentive Plan 2016 \| Restricted stock units
Restricted Stock
Grants in period (in shares)		450,000
Recognized and unrecognized unearned compensation				$ 2,117
Recognized and unrecognized unearned compensation, reversed				1,432
General and administrative expense from unearned compensation				685
Compensation expense				140	$ 142
Unearned compensation				$ 35	$ 177
Incentive Plan 2016 \| CAGR in Shareholder Return \| Restricted stock units
Restricted Stock
Grants in period (in shares)		200,000
Incentive Plan 2016 \| CAGR in Adjusted Funds from Operations \| Restricted stock units
Restricted Stock
Grants in period (in shares)		200,000
Incentive Plan 2016 \| CAGR Relative to FTSE NAREIT Equity Apartment Index \| Restricted stock units
Restricted Stock
Grants in period (in shares)		50,000
Contingently issuable shares (in shares)				450,000
Contingently issuable shares, excluded from diluted earnings calculation (in shares)				250,000
Contingently issuable shares included in diluted earnings calculation (in shares)				200,000