Summary of Significant Accounting Policies - Costs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Summary of Significant Accounting Policies
Capitalized deferred leasing cost	$ 51.8	$ 42.8	$ 40.8
Deferred leasing costs	257.0	249.3
Accumulated amortization, deferred leasing costs and intangibles	514.3	453.0
Amortization expense on deferred leasing costs	$ 79.2	$ 83.4	$ 76.0