Segment Information - Assets (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($) segment	Dec. 31, 2017 USD ($)
Reconciliation of assets from segment to consolidated
Number of activity segments | segment	48
Net real estate	$ 13,843,517	$ 12,676,499
Goodwill	14,630	14,970
Other corporate assets	202,739	171,767
Total assets	15,260,483	14,058,166
Apparel
Reconciliation of assets from segment to consolidated
Net real estate	157,167	164,919
Intangible assets	32,691	36,600
Automotive service
Reconciliation of assets from segment to consolidated
Net real estate	210,668	213,156
Intangible assets	61,951	64,388
Goodwill	437	437
Automotive tire services
Reconciliation of assets from segment to consolidated
Net real estate	238,939	247,557
Intangible assets	8,696	10,383
Goodwill	862	862
Beverages
Reconciliation of assets from segment to consolidated
Net real estate	284,910	289,170
Intangible assets	1,765	2,022
Convenience Stores
Reconciliation of assets from segment to consolidated
Net real estate	1,756,732	997,170
Intangible assets	108,714	45,445
Goodwill	1,983	2,004
Dollar stores
Reconciliation of assets from segment to consolidated
Net real estate	1,117,250	1,105,097
Intangible assets	48,842	47,905
Drug stores
Reconciliation of assets from segment to consolidated
Net real estate	1,490,261	1,518,443
Intangible assets	165,558	173,893
Financial services
Reconciliation of assets from segment to consolidated
Net real estate	414,613	384,867
Intangible assets	20,426	24,867
General merchandise
Reconciliation of assets from segment to consolidated
Net real estate	317,424	313,181
Intangible assets	43,122	50,184
Grocery stores
Reconciliation of assets from segment to consolidated
Net real estate	774,526	793,286
Intangible assets	144,551	140,780
Health and fitness
Reconciliation of assets from segment to consolidated
Net real estate	882,515	896,430
Intangible assets	71,609	76,276
Home improvement
Reconciliation of assets from segment to consolidated
Net real estate	424,494	407,002
Intangible assets	57,928	61,045
Motor vehicle dealerships
Reconciliation of assets from segment to consolidated
Net real estate	198,204	204,651
Intangible assets	28,154	31,720
Restaurants-casual dining
Reconciliation of assets from segment to consolidated
Net real estate	559,616	494,977
Intangible assets	18,153	20,079
Goodwill	1,841	2,062
Restaurants-quick service
Reconciliation of assets from segment to consolidated
Net real estate	964,980	681,763
Intangible assets	54,448	51,711
Goodwill	1,052	1,064
Theaters
Reconciliation of assets from segment to consolidated
Net real estate	555,990	566,585
Intangible assets	25,811	26,448
Transportation services
Reconciliation of assets from segment to consolidated
Net real estate	758,133	776,068
Intangible assets	73,577	87,162
Wholesale club
Reconciliation of assets from segment to consolidated
Net real estate	412,203	426,551
Intangible assets	26,484	29,596
Other non-reportable segments
Reconciliation of assets from segment to consolidated
Net real estate	2,324,892	2,195,626
Intangible assets	207,117	214,426
Goodwill	$ 8,455	$ 8,541