Segment Information - Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Segment revenue information
Rental revenue	$ 260,056	$ 241,431	$ 516,857	$ 476,554
Tenant reimbursements	11,112	11,607	20,217	21,570
Other revenue	(129)	822	1,081	2,604
Total revenue	271,039	253,860	538,155	500,728
Apparel
Segment revenue information
Rental revenue	4,879	4,932	9,754	9,863
Automotive service
Segment revenue information
Rental revenue	4,814	4,795	9,491	9,116
Automotive tire services
Segment revenue information
Rental revenue	7,220	7,280	14,484	14,370
Beverages
Segment revenue information
Rental revenue	6,404	6,328	12,809	12,656
Child care
Segment revenue information
Rental revenue	4,845	4,863	9,937	9,884
Convenience stores
Segment revenue information
Rental revenue	22,789	22,557	45,653	45,073
Dollar stores
Segment revenue information
Rental revenue	22,728	21,943	45,324	43,890
Drug stores
Segment revenue information
Rental revenue	28,638	25,885	57,059	48,483
Financial services
Segment revenue information
Rental revenue	4,252	4,263	8,565	8,528
General merchandise
Segment revenue information
Rental revenue	4,301	3,842	8,560	7,866
Grocery stores
Segment revenue information
Rental revenue	7,408	7,527	15,054	14,882
Health and fitness
Segment revenue information
Rental revenue	21,545	17,396	42,849	33,411
Health care
Segment revenue information
Rental revenue	4,049	4,016	8,065	8,032
Home improvement
Segment revenue information
Rental revenue	6,099	5,506	12,153	10,684
Motor vehicle dealerships
Segment revenue information
Rental revenue	5,595	3,945	9,809	7,760
Restaurants - casual dining
Segment revenue information
Rental revenue	10,633	9,463	20,468	18,912
Restaurants - quick service
Segment revenue information
Rental revenue	12,482	9,620	25,276	19,982
Sporting goods
Segment revenue information
Rental revenue	5,316	4,878	9,872	8,577
Theaters
Segment revenue information
Rental revenue	12,708	12,286	26,157	24,476
Transportation services
Segment revenue information
Rental revenue	13,752	12,251	26,842	25,202
Wholesale clubs
Segment revenue information
Rental revenue	9,369	9,341	18,738	18,683
Other non-reportable segments
Segment revenue information
Rental revenue	$ 40,230	$ 38,514	$ 79,938	$ 76,224