Derivative Financial Instruments (Summary of Amount of Gain (Loss) Recognized in Accumulated Other Comprehensive Income) (Details) - Derivatives in Cash Flow Hedging Relationships [Member] - Interest Rate Swap Contracts [Member] - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Derivative Instruments Gain Loss [Line Items]
Amount of Gain (Loss) Recognized in AOCI			$ 14.1	$ (12.9)
Interest Expense [Member]
Derivative Instruments Gain Loss [Line Items]
Gain reclassified from AOCI into net earnings (loss)	$ 2.2	$ 1.9	$ 6.3	$ 3.7