UNCONSOLIDATED INVESTMENTS - Cash Distributions by Investment Type and Location (Details) $ in Millions	12 Months Ended
	Dec. 31, 2021 USD ($)
Schedule of Equity Method Investments [Line Items]
Operating	$ 82.2
Investing	82.8
Multifamily
Schedule of Equity Method Investments [Line Items]
Operating	35.4
Investing	45.7
Commercial
Schedule of Equity Method Investments [Line Items]
Operating	22.7
Investing	9.6
Funds
Schedule of Equity Method Investments [Line Items]
Operating	24.1
Investing	5.3
Residential and Other
Schedule of Equity Method Investments [Line Items]
Operating	0.0
Investing	22.2
Western U.S.
Schedule of Equity Method Investments [Line Items]
Operating	63.2
Investing	59.5
Western U.S. | Multifamily
Schedule of Equity Method Investments [Line Items]
Operating	29.7
Investing	22.5
Western U.S. | Commercial
Schedule of Equity Method Investments [Line Items]
Operating	9.4
Investing	9.6
Western U.S. | Funds
Schedule of Equity Method Investments [Line Items]
Operating	24.1
Investing	5.3
Western U.S. | Residential and Other
Schedule of Equity Method Investments [Line Items]
Operating	0.0
Investing	22.1
Ireland
Schedule of Equity Method Investments [Line Items]
Operating	15.7
Investing	23.2
Ireland | Multifamily
Schedule of Equity Method Investments [Line Items]
Operating	5.7
Investing	23.2
Ireland | Commercial
Schedule of Equity Method Investments [Line Items]
Operating	10.0
Investing	0.0
Ireland | Funds
Schedule of Equity Method Investments [Line Items]
Operating	0.0
Investing	0.0
Ireland | Residential and Other
Schedule of Equity Method Investments [Line Items]
Operating	0.0
Investing	0.0
United Kingdom
Schedule of Equity Method Investments [Line Items]
Operating	3.3
Investing	0.1
United Kingdom | Multifamily
Schedule of Equity Method Investments [Line Items]
Operating	0.0
Investing	0.0
United Kingdom | Commercial
Schedule of Equity Method Investments [Line Items]
Operating	3.3
Investing	0.0
United Kingdom | Funds
Schedule of Equity Method Investments [Line Items]
Operating	0.0
Investing	0.0
United Kingdom | Residential and Other
Schedule of Equity Method Investments [Line Items]
Operating	0.0
Investing	$ 0.1