Supplemental Disclosures of Cash Flow Information - Narrative (Details) £ in Millions	6 Months Ended
Jun. 30, 2021 GBP (£) property mortgage	Jun. 30, 2021 USD ($) property mortgage	Jun. 30, 2020 USD ($) mortgage
Supplemental Disclosures of Cash Flow Information
Cash paid for interest		$ 139,400,000	$ 149,400,000
Cash paid for income taxes		9,700,000	5,300,000
Cash paid or merger-related costs		$ 4,400,000	$ 0
Non-cash activities
Number of mortgages assumed	1	1	0
Non-refundable deposits applied to acquisitions			$ 13,800,000
Mortgages payable
Non-cash activities
Number of mortgages assumed \| mortgage	1	1
Mortgage loans assumed \| £	£ 31.0
Derivative
Non-cash activities
Decrease in fair value of net derivative liabilities		$ 60,400,000	$ 28,600,000

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Amount of escrow deposit disbursements related to property acquisition in noncash investing or financing transactions.

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The amount of cash paid during the current period to foreign, federal, state, and local authorities as taxes on income.

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Amount of cash paid for interest, excluding capitalized interest, classified as operating activity. Includes, but is not limited to, payment to settle zero-coupon bond for accreted interest of debt discount and debt instrument with insignificant coupon interest rate in relation to effective interest rate of borrowing attributable to accreted interest of debt discount.

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Amount of addition (reduction) to the amount at which a liability could be incurred (settled) in a current transaction between willing parties.

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The fair value of loans assumed in noncash investing or financing activities.

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The amount of cash paid during the reporting period for charges associated with the mergers.

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