Schedule III - Real Estate and Accumulated Depreciation - Changes in Real Estate Rollforward (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance at the beginning of period	$ 5,981.7	$ 6,578.6	$ 5,805.4
Additions during the period:
Other acquisitions	176.2	210.3	179.5
Improvements	270.0	355.1	615.7
Foreign currency	26.7	(191.7)	426.9
Deductions during the period:
Cost of real estate sold	(1,024.1)	(970.6)	(448.9)
Balance at close of period	$ 5,430.5	$ 5,981.7	$ 6,578.6