Note 5 - Other Real Estate Investments (Details Textual) - Preferred Equity Investments [Member] $ in Millions	6 Months Ended
Jun. 30, 2021 USD ($)	Jun. 30, 2020 USD ($)
Equity Method Investments	$ 123.4
Number of Real Estate Properties	62
Income (Loss) from Equity Method Investments, Total	$ 7.7	$ 15.9
Equity Method Investment, Realized Gain (Loss) on Disposal, Total	$ 1.2	$ 7.5
Leased Properties [Member]
Number of Real Estate Properties	52
San Antonio, Texas [Member]
Payments to Acquire Equity Method Investments	$ 54.9

Amount of gain (loss) on sale or disposal of an equity method investment.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized.

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Amount of income (loss) for proportionate share of equity method investee's income (loss).

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The number of real estate properties owned as of the balance sheet date.

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The cash outflow associated with the purchase of or advances to an equity method investments, which are investments in joint ventures and entities in which the entity has an equity ownership interest normally of 20 to 50 percent and exercises significant influence.

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