Notes Payable - Narrative (Details) - Notes payable € in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023 USD ($)	Jun. 30, 2022 USD ($)	Jun. 30, 2023 USD ($)	Jun. 30, 2022 USD ($)	Jul. 31, 2023 EUR (€)	Jun. 30, 2023 GBP (£)	Jan. 31, 2022 GBP (£)	Jul. 31, 2021 GBP (£)	Oct. 31, 2020 GBP (£)
Debt
Weighted average interest rate (as a percent)						3.60%
Weighted average remaining years until maturity			6 years 8 months 12 days
Interest incurred on notes and bonds | $	$ 144.1	$ 103.0	$ 274.4	$ 206.1
1.625% Notes due 2030
Debt
Principal (Currency Denomination)						£ 400,000,000			£ 400,000,000
Interest rate (as a percent)						1.625%			0.01625%
1.125% Notes due 2027
Debt
Principal (Currency Denomination)						£ 400,000,000		£ 400,000,000
Interest rate (as a percent)						1.125%		0.01125%
1.750% Notes due 2033
Debt
Principal (Currency Denomination)						£ 350,000,000		£ 350,000,000
Interest rate (as a percent)						1.75%		0.0175%
1.875% Notes due 2027
Debt
Principal (Currency Denomination)						£ 250,000,000	£ 250,000,000
Interest rate (as a percent)						1.875%	0.01875%
2.500% Notes due 2042
Debt
Principal (Currency Denomination)						£ 250,000,000	£ 250,000,000
Interest rate (as a percent)						2.50%	0.025%
4.875% Notes due 2030 | Subsequent event
Debt
Principal (Currency Denomination) | €					€ 550.0
Interest rate (as a percent)					4.875%
5.125% Notes due 2034 | Subsequent event
Debt
Principal (Currency Denomination) | €					€ 550.0
Interest rate (as a percent)					5.125%
Maximum
Debt
Debt to total adjusted assets ratio (as a percent)			60.00%
Secured debt to total adjusted assets ratio (as a percent)			40.00%
Minimum
Debt
Debt service coverage ratio			1.5
Total unencumbered assets as a percentage of outstanding unsecured debt			150.00%