Segment Information - Assets (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2019 USD ($) segment	Dec. 31, 2018 USD ($)
Segment Reporting [Abstract]
Number of activity segments | segment	49
Reconciliation of assets from segment to consolidated
Net real estate	$ 14,940,266	$ 13,843,517
Intangible assets	1,308,564	1,199,597
Goodwill	14,536	14,630
Other corporate assets	485,264	202,739
Total assets	16,748,630	15,260,483
Automotive service
Reconciliation of assets from segment to consolidated
Net real estate	282,770	210,668
Intangible assets	59,969	61,951
Goodwill	436	437
Automotive tire services
Reconciliation of assets from segment to consolidated
Net real estate	234,890	238,939
Intangible assets	7,881	8,696
Goodwill	862	862
Beverages
Reconciliation of assets from segment to consolidated
Net real estate	281,481	284,910
Intangible assets	1,637	1,765
Child care
Reconciliation of assets from segment to consolidated
Net real estate	179,456	151,640
Intangible assets	17,178	12,277
Goodwill	4,830	4,863
Convenience stores
Reconciliation of assets from segment to consolidated
Net real estate	1,729,843	1,756,732
Intangible assets	106,950	108,714
Goodwill	1,981	1,983
Dollar stores
Reconciliation of assets from segment to consolidated
Net real estate	1,127,619	1,117,250
Intangible assets	49,312	48,842
Drug stores
Reconciliation of assets from segment to consolidated
Net real estate	1,463,695	1,490,261
Intangible assets	158,895	165,558
Financial services
Reconciliation of assets from segment to consolidated
Net real estate	401,990	414,613
Intangible assets	18,708	20,426
General merchandise
Reconciliation of assets from segment to consolidated
Net real estate	352,454	317,424
Intangible assets	44,766	43,122
Grocery stores - U.S.
Reconciliation of assets from segment to consolidated
Net real estate	844,322	774,526
Intangible assets	169,280	144,551
Grocery stores - U.K.
Reconciliation of assets from segment to consolidated
Net real estate	450,002	0
Intangible assets	102,892	0
Health and fitness
Reconciliation of assets from segment to consolidated
Net real estate	982,281	882,515
Intangible assets	66,113	71,609
Home improvement
Reconciliation of assets from segment to consolidated
Net real estate	491,104	424,494
Intangible assets	74,158	57,928
Restaurants-casual dining
Reconciliation of assets from segment to consolidated
Net real estate	542,624	559,616
Intangible assets	17,317	18,153
Goodwill	1,815	1,841
Restaurants-quick service
Reconciliation of assets from segment to consolidated
Net real estate	1,001,528	964,980
Intangible assets	54,029	54,448
Goodwill	1,044	1,052
Theaters
Reconciliation of assets from segment to consolidated
Net real estate	869,915	555,990
Intangible assets	33,124	25,811
Transportation services
Reconciliation of assets from segment to consolidated
Net real estate	740,720	758,133
Intangible assets	67,684	73,577
Wholesale club
Reconciliation of assets from segment to consolidated
Net real estate	405,719	412,203
Intangible assets	24,928	26,484
Other non-reportable segments
Reconciliation of assets from segment to consolidated
Net real estate	2,557,853	2,528,623
Intangible assets	233,743	255,685
Goodwill	$ 3,568	$ 3,592