UNCONSOLIDATED INVESTMENTS - Note Conversion to Real Estate (Details) $ in Millions	12 Months Ended
	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($) a note
Schedule of Equity Method Investments [Line Items]
Total Joint Venture Acquisition Related Gain	$ 83.0	$ 170.3	$ 56.6
The Company's Portion of Total Gain	108.1	$ 218.1	$ 56.6
3 Mortgage Notes Converted Into Real Estate Owned [Member]
Schedule of Equity Method Investments [Line Items]
Number of mortgage notes converted into real estate owned | note			3
Total Joint Venture Acquisition Related Gain	72.5
The Company's Portion of Total Gain	36.2
3 Mortgage Notes Converted Into Real Estate Owned [Member] | Ireland [Member]
Schedule of Equity Method Investments [Line Items]
Area of units acquired (in acres) | a			3.5
Total Joint Venture Acquisition Related Gain	30.1
The Company's Portion of Total Gain	15.0
3 Mortgage Notes Converted Into Real Estate Owned [Member] | United Kingdom [Member]
Schedule of Equity Method Investments [Line Items]
Total Joint Venture Acquisition Related Gain	32.3
The Company's Portion of Total Gain	16.2
3 Mortgage Notes Converted Into Real Estate Owned [Member] | Scotland [Member]
Schedule of Equity Method Investments [Line Items]
Total Joint Venture Acquisition Related Gain	10.1
The Company's Portion of Total Gain	$ 5.0