Segment Information - Assets (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2016 USD ($) segment	Dec. 31, 2015 USD ($) segment
Reconciliation of assets from segment to consolidated
Number of activity segments | segment	47
Net real estate	$ 11,263,658	$ 10,618,884
Goodwill	15,165	15,321
Other corporate assets	169,982	176,757
Total assets	12,536,453	11,845,379
Apparel
Reconciliation of assets from segment to consolidated
Net real estate	176,015	180,175
Intangible assets	44,869	48,116
Automotive service
Reconciliation of assets from segment to consolidated
Net real estate	154,929	129,068
Intangible assets	33,451	19,131
Goodwill	445	448
Automotive tire services
Reconciliation of assets from segment to consolidated
Net real estate	240,156	247,200
Intangible assets	11,950	13,202
Goodwill	862	865
Beverages
Reconciliation of assets from segment to consolidated
Net real estate	294,516	297,724
Intangible assets	2,345	2,538
Child care
Reconciliation of assets from segment to consolidated
Net real estate	50,510	52,391
Goodwill	4,988	5,034
Convenience stores
Reconciliation of assets from segment to consolidated
Net real estate	704,757	723,092
Intangible assets	14,740	15,843
Goodwill	2,008	2,009
Dollar stores
Reconciliation of assets from segment to consolidated
Net real estate	1,130,030	1,158,948
Intangible assets	52,645	56,420
Drug stores
Reconciliation of assets from segment to consolidated
Net real estate	1,554,847	1,386,387
Intangible assets	187,364	189,631
Financial services
Reconciliation of assets from segment to consolidated
Net real estate	247,458	254,022
Intangible assets	30,947	34,626
General merchandise
Reconciliation of assets from segment to consolidated
Net real estate	218,785	195,030
Intangible assets	39,780	41,301
Grocery stores
Reconciliation of assets from segment to consolidated
Net real estate	428,373	333,388
Intangible assets	61,380	42,823
Health and fitness
Reconciliation of assets from segment to consolidated
Net real estate	828,317	839,872
Intangible assets	64,949	65,037
Health care
Reconciliation of assets from segment to consolidated
Net real estate	216,629	220,018
Intangible assets	26,312	29,950
Home improvement
Reconciliation of assets from segment to consolidated
Net real estate	286,140	268,974
Intangible assets	44,493	42,630
Motor vehicle dealerships
Reconciliation of assets from segment to consolidated
Net real estate	191,474	137,315
Intangible assets	25,795	13,182
Restaurants - casual dining
Reconciliation of assets from segment to consolidated
Net real estate	524,832	418,883
Intangible assets	22,553	9,392
Goodwill	2,137	2,215
Restaurants - quick service
Reconciliation of assets from segment to consolidated
Net real estate	549,319	467,330
Intangible assets	44,153	32,612
Goodwill	1,071	1,082
Theaters
Reconciliation of assets from segment to consolidated
Net real estate	371,086	371,617
Intangible assets	14,785	17,673
Transportation services
Reconciliation of assets from segment to consolidated
Net real estate	801,643	686,041
Intangible assets	105,326	92,602
Wholesale clubs
Reconciliation of assets from segment to consolidated
Net real estate	442,809	452,563
Intangible assets	33,596	36,215
Other non-reportable segments
Reconciliation of assets from segment to consolidated
Net real estate	1,851,033	1,798,846
Intangible assets	226,215	231,493
Goodwill	$ 3,654	$ 3,668
Number of non-reportable segments | segment	27	27