Segment Information - Assets (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2018 USD ($) segment	Dec. 31, 2017 USD ($)
Reconciliation of assets from segment to consolidated
Number of activity segments | segment	48
Net real estate	$ 13,230,042	$ 12,676,499
Goodwill	14,902	14,970
Other corporate assets	200,550	171,767
Total assets	14,674,074	14,058,166
Apparel
Reconciliation of assets from segment to consolidated
Net real estate	161,920	164,919
Intangible assets	34,641	36,600
Automotive service
Reconciliation of assets from segment to consolidated
Net real estate	209,964	213,156
Intangible assets	62,664	64,388
Goodwill	437	437
Automotive tire services
Reconciliation of assets from segment to consolidated
Net real estate	243,271	247,557
Intangible assets	9,520	10,383
Goodwill	862	862
Beverages
Reconciliation of assets from segment to consolidated
Net real estate	287,032	289,170
Intangible assets	1,894	2,022
Child care
Reconciliation of assets from segment to consolidated
Net real estate	60,058	61,527
Goodwill	4,899	4,924
Convenience stores
Reconciliation of assets from segment to consolidated
Net real estate	1,397,354	997,170
Intangible assets	95,392	45,445
Goodwill	2,002	2,004
Dollar stores
Reconciliation of assets from segment to consolidated
Net real estate	1,101,066	1,105,097
Intangible assets	47,357	47,905
Drug stores
Reconciliation of assets from segment to consolidated
Net real estate	1,511,955	1,518,443
Intangible assets	171,741	173,893
Financial services
Reconciliation of assets from segment to consolidated
Net real estate	428,731	384,867
Intangible assets	22,563	24,867
General merchandise
Reconciliation of assets from segment to consolidated
Net real estate	318,584	313,181
Intangible assets	45,893	50,184
Grocery stores
Reconciliation of assets from segment to consolidated
Net real estate	773,501	793,286
Intangible assets	144,239	140,780
Health and fitness
Reconciliation of assets from segment to consolidated
Net real estate	886,585	896,430
Intangible assets	74,992	76,276
Home improvement
Reconciliation of assets from segment to consolidated
Net real estate	428,730	407,002
Intangible assets	61,666	61,045
Motor vehicle dealerships
Reconciliation of assets from segment to consolidated
Net real estate	201,073	204,651
Intangible assets	29,937	31,720
Restaurants-casual dining
Reconciliation of assets from segment to consolidated
Net real estate	475,028	494,977
Intangible assets	19,100	20,079
Goodwill	2,047	2,062
Restaurants-quick service
Reconciliation of assets from segment to consolidated
Net real estate	803,886	681,763
Intangible assets	62,303	51,711
Goodwill	1,057	1,064
Theaters
Reconciliation of assets from segment to consolidated
Net real estate	561,477	566,585
Intangible assets	25,555	26,448
Transportation services
Reconciliation of assets from segment to consolidated
Net real estate	766,883	776,068
Intangible assets	80,111	87,162
Wholesale club
Reconciliation of assets from segment to consolidated
Net real estate	420,048	426,551
Intangible assets	28,040	29,596
Other non-reportable segments
Reconciliation of assets from segment to consolidated
Net real estate	2,192,896	2,134,099
Intangible assets	210,972	214,426
Goodwill	$ 3,598	$ 3,617