Derivatives and Hedging Activities (Details) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020 USD ($) swap	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($) swap	Sep. 30, 2019 USD ($)
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months			$ 21.8
Number of interest rate swaps | swap	4		4
Loss recognized in OCI (effective portion)	$ 2.3	$ 8.5	$ 29.2	$ 39.6
Loss reclassified from accumulated OCI to interest expense (effective portion)	5.6	$ 1.7	14.6	$ 4.5
Interest Rate Swap
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Derivative notional amount	$ 1,200.0		$ 1,200.0