Investments in Real Estate - Acquisitions Allocation (Details) $ in Thousands, £ in Millions	6 Months Ended
	Jun. 30, 2022 USD ($)	Jun. 30, 2022 GBP (£)	Jun. 30, 2021 USD ($)	Jun. 30, 2021 GBP (£)
Acquisitions
Weighted average amortization period for acquired lease intangible assets	10 years 3 months 18 days	10 years 3 months 18 days	12 years 8 months 12 days	12 years 8 months 12 days
Weighted average amortization period for acquired lease intangible liabilities	11 years 4 months 24 days	11 years 4 months 24 days	14 years	14 years
Real Estate Investment | U.S.
Acquisitions
Land	$ 480,300		$ 384,500
Buildings and improvements	843,900		539,500
Lease intangible assets	185,000		171,800
Other assets	214,700		38,500
Lease intangible liabilities	(27,300)		(14,400)
Other liabilities	(21,100)		(21,600)
Net	1,675,500		1,098,300
Allocated to other assets, financing receivables with above-market terms	182,600
Allocated to other assets, finance lease right-of-use assets	32,100
Deferred rent on below market leases	14,600
Lease liabilities under finance leases	8,600
Mortgage discounts	$ 2,100
Real Estate Investment | U.K.
Acquisitions
Land | £		£ 476.7		£ 219.7
Buildings and improvements | £		368.2		375.4
Lease intangible assets | £		179.4		125.6
Other assets | £		166.2		0.0
Lease intangible liabilities | £		(50.2)		(5.3)
Other liabilities		0.0	$ (300)
Net | £		1,140.3		715.1
Allocated to land, right of use assets under long-term ground leases | £		33.2		£ 1.3
Allocated to other assets, financing receivables with above-market terms | £		3.8
Allocated to other assets, finance lease right-of-use assets | £		£ 162.4