Note 15 - Noncontrolling Interests and Redeemable Noncontrolling Interests - Convertible Non-convertible Units (Details)	12 Months Ended
	Dec. 31, 2020 $ / shares shares
Class B-1 Preferred Units [Member]
Par Value Per Unit (in dollars per share) | $ / shares	$ 10,000	[1]
Number of Units Remaining (in shares) | shares	189	[1]
Return Per Annum	7.00%	[1]
Class B-2 Preferred Units [Member]
Par Value Per Unit (in dollars per share) | $ / shares	$ 10,000	[2]
Number of Units Remaining (in shares) | shares	42	[2]
Return Per Annum	7.00%	[2]
Class C DownReit Units [Member]
Par Value Per Unit (in dollars per share) | $ / shares	$ 30.52	[1]
Number of Units Remaining (in shares) | shares	52,797	[1]

[1] These units are redeemable for cash by the holder or at the Company’s option, shares of the Company’s common stock, based upon the conversion calculation as defined in the agreement. These units are included in Noncontrolling interests on the Company’s Consolidated Balance Sheets.

[2] These units are redeemable for cash by the holder or callable by the Company and are included in Redeemable noncontrolling interests on the Company's Consolidated Balance Sheets.