Consolidated Statements Of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Statement of Comprehensive Income [Abstract]
Net Income	$ 180.4	$ 177.0	$ 245.0	$ 259.8
Foreign Currency Translation
Foreign currency translation gain / (loss) arising during period	(25.5)	(84.2)	7.1	(151.2)
Adjustment for accumulated foreign currency translation loss reclassified into earnings	0.0	0.0	11.9	0.0
Net foreign currency translation gain / (loss)	(25.5)	(84.2)	19.0	(151.2)
Cash Flow Hedges
Change in unrealized gain / (loss) on interest rate derivatives	(3.7)	40.7	6.7	75.7
Less: Interest rate derivative (gain) / loss reclassified to earnings	(4.5)	0.2	(10.0)	(0.6)
Net unrealized gain / (loss) on interest rate derivatives	(8.2)	40.9	(3.3)	75.1
Total Comprehensive Income	146.7	133.7	260.7	183.7
Less: Comprehensive income attributable to noncontrolling interests	(12.7)	(10.2)	(13.8)	(10.8)
Comprehensive Income attributable to SUI	$ 134.0	$ 123.5	$ 246.9	$ 172.9