Derivatives and Hedging Activities (Details) $ in Millions	12 Months Ended
Dec. 31, 2020 USD ($) swap	Dec. 31, 2019 USD ($) swap	Dec. 31, 2018 USD ($)
Derivative [Line Items]
Amount estimated to be reclassified as a reduction to interest expense over next 12 months	$ 21.8
Number of interest rate swaps held \| swap	4	4
Loss recognized in OCI (effective portion)	$ 30.5	$ 35.8
Loss recognized in OCI (effective portion)			$ 23.1
Loss reclassified from accumulated OCI to interest expense (effective portion)	20.2	7.5
Loss reclassified from accumulated OCI to interest expense (effective portion)			$ 0.6
Interest Rate Swap
Derivative [Line Items]
Current notional amount	$ 1,200.0	$ 1,200.0

The estimated net amount of existing gains or losses on cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months.

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The effective portion of loss reclassified from accumulated other comprehensive income into income on derivative instruments designated and qualifying as hedging instruments.

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Nominal or face amount used to calculate payment on derivative.

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Number of interest rate derivative instruments held by the entity at the reporting date.

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Amount, before tax and reclassification, of gain (loss) from derivative instrument designated and qualifying cash flow hedge included in assessment of hedge effectiveness.

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Amount, before tax, of reclassification of gain (loss) from accumulated other comprehensive income (AOCI) for derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness.

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Amount of unrealized gain (loss) related to the increase or decrease in fair value of interest rate derivatives designated as cash flow hedging instruments, which was recorded in accumulated other comprehensive income to the extent that the cash flow hedge was determined to be effective.

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