Segment Information - Assets (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($) segment	Dec. 31, 2019 USD ($)
Reconciliation of assets from segment to consolidated
Number of activity segments | segment	51
Net real estate	$ 17,485,156	$ 16,496,772
Lease intangible assets, net	1,710,655	1,493,383
Other corporate assets	1,544,474	564,641
Total assets	20,740,285	18,554,796
Automotive service
Reconciliation of assets from segment to consolidated
Net real estate	328,340	288,453
Lease intangible assets, net	55,018	58,854
Beverages
Reconciliation of assets from segment to consolidated
Net real estate	347,366	279,373
Lease intangible assets, net	9,401	1,509
Child care
Reconciliation of assets from segment to consolidated
Net real estate	216,718	208,326
Lease intangible assets, net	19,848	21,997
Convenience Stores
Reconciliation of assets from segment to consolidated
Net real estate	2,101,005	2,057,157
Lease intangible assets, net	121,151	131,808
Dollar stores
Reconciliation of assets from segment to consolidated
Net real estate	1,420,210	1,427,950
Lease intangible assets, net	77,176	82,701
Drug stores
Reconciliation of assets from segment to consolidated
Net real estate	1,555,106	1,618,854
Lease intangible assets, net	167,975	183,319
Financial services
Reconciliation of assets from segment to consolidated
Net real estate	374,508	389,634
Lease intangible assets, net	14,611	17,130
General merchandise
Reconciliation of assets from segment to consolidated
Net real estate	730,806	475,418
Lease intangible assets, net	108,646	66,135
Grocery stores - U.S.
Reconciliation of assets from segment to consolidated
Net real estate	907,634	922,349
Lease intangible assets, net	181,764	180,197
Grocery stores - U.K.
Reconciliation of assets from segment to consolidated
Net real estate	1,131,760	663,210
Lease intangible assets, net	282,211	153,407
Health and fitness
Reconciliation of assets from segment to consolidated
Net real estate	1,050,791	1,019,796
Lease intangible assets, net	67,537	74,428
Home improvement - U.S.
Reconciliation of assets from segment to consolidated
Net real estate	608,222	495,305
Lease intangible assets, net	97,228	72,979
Restaurants-casual dining
Reconciliation of assets from segment to consolidated
Net real estate	515,226	576,526
Lease intangible assets, net	20,553	23,289
Restaurants-quick service
Reconciliation of assets from segment to consolidated
Net real estate	1,062,918	1,059,155
Lease intangible assets, net	47,517	52,353
Theaters - U.S.
Reconciliation of assets from segment to consolidated
Net real estate	767,117	878,103
Lease intangible assets, net	28,292	36,089
Transportation services
Reconciliation of assets from segment to consolidated
Net real estate	729,640	769,614
Lease intangible assets, net	53,902	66,055
Wholesale club
Reconciliation of assets from segment to consolidated
Net real estate	407,584	396,690
Lease intangible assets, net	36,165	23,372
Other non-reportable segments
Reconciliation of assets from segment to consolidated
Net real estate	3,230,205	2,970,859
Lease intangible assets, net	$ 321,660	$ 247,761