Segment Information (Details) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2015 USD ($) segment	Dec. 31, 2014 USD ($) segment
Segment Information
Number of activity segments | segment	48	48
Reconciliation of assets from segment to consolidated
Net real estate	$ 10,489,666	$ 9,781,540
Goodwill	15,386	15,470
Other corporate assets	171,549	175,888
Total assets	11,728,314	11,012,622
Apparel
Reconciliation of assets from segment to consolidated
Net real estate	185,615	188,387
Intangible assets	50,481	52,680
Automotive service
Reconciliation of assets from segment to consolidated
Net real estate	135,378	121,537
Intangible assets	16,748	2,909
Goodwill	448	452
Automotive tire services
Reconciliation of assets from segment to consolidated
Net real estate	250,745	254,857
Intangible assets	14,036	14,871
Goodwill	865	865
Beverages
Reconciliation of assets from segment to consolidated
Net real estate	299,862	302,001
Intangible assets	2,668	2,796
Child care
Reconciliation of assets from segment to consolidated
Net real estate	53,328	54,523
Goodwill	5,053	5,095
Convenience stores
Reconciliation of assets from segment to consolidated
Net real estate	740,196	752,047
Intangible assets	16,788	17,534
Goodwill	2,022	2,023
Dollar stores
Reconciliation of assets from segment to consolidated
Net real estate	1,148,850	1,165,560
Intangible assets	56,013	58,691
Drug stores
Reconciliation of assets from segment to consolidated
Net real estate	1,354,142	1,036,697
Intangible assets	194,973	194,905
Financial services
Reconciliation of assets from segment to consolidated
Net real estate	258,215	262,095
Intangible assets	37,095	39,564
Grocery stores
Reconciliation of assets from segment to consolidated
Net real estate	333,463	338,624
Intangible assets	44,698	46,730
Health and fitness
Reconciliation of assets from segment to consolidated
Net real estate	853,348	546,583
Intangible assets	67,569	66,460
Health care
Reconciliation of assets from segment to consolidated
Net real estate	223,312	227,084
Intangible assets	32,484	35,016
Home improvement
Reconciliation of assets from segment to consolidated
Net real estate	269,543	226,577
Intangible assets	45,277	35,726
Restaurants-casual dining
Reconciliation of assets from segment to consolidated
Net real estate	434,729	448,484
Intangible assets	10,020	10,649
Goodwill	2,244	2,279
Restaurants-quick service
Reconciliation of assets from segment to consolidated
Net real estate	380,911	336,753
Intangible assets	23,821	16,415
Goodwill	1,085	1,085
Sporting goods
Reconciliation of assets from segment to consolidated
Net real estate	143,417	136,110
Intangible assets	12,644	12,311
Theaters
Reconciliation of assets from segment to consolidated
Net real estate	372,095	375,982
Intangible assets	19,598	21,601
Transportation services
Reconciliation of assets from segment to consolidated
Net real estate	664,880	661,053
Intangible assets	94,837	101,040
Wholesale club
Reconciliation of assets from segment to consolidated
Net real estate	459,066	465,569
Intangible assets	37,961	39,707
Other non-reportable segments
Reconciliation of assets from segment to consolidated
Net real estate	1,928,571	1,881,017
Intangible assets	274,002	270,119
Goodwill	$ 3,669	$ 3,671
Number of non-reportable segments | segment	29	29