Segment Information - Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Segment revenue information
Rental revenue	$ 285,821	$ 256,801
Tenant reimbursements	11,229	9,105
Other revenue	975	1,210
Total revenue	298,025	267,116
Apparel stores
Segment revenue information
Rental revenue	4,966	4,875
Automotive service
Segment revenue information
Rental revenue	5,543	4,677
Automotive tire services
Segment revenue information
Rental revenue	7,159	7,264
Beverages
Segment revenue information
Rental revenue	7,758	6,404
Child care
Segment revenue information
Rental revenue	5,487	5,092
Convenience stores
Segment revenue information
Rental revenue	28,303	22,864
Dollar stores
Segment revenue information
Rental revenue	22,752	22,595
Drug stores
Segment revenue information
Rental revenue	31,631	28,421
Financial services
Segment revenue information
Rental revenue	7,159	4,313
General merchandise
Segment revenue information
Rental revenue	5,361	4,259
Grocery stores
Segment revenue information
Rental revenue	10,162	7,645
Health and fitness
Segment revenue information
Rental revenue	21,605	21,304
Home improvement
Segment revenue information
Rental revenue	6,919	6,054
Motor vehicle dealerships
Segment revenue information
Rental revenue	6,736	4,214
Restaurants-casual dining
Segment revenue information
Rental revenue	10,890	9,835
Restaurants-quick service
Segment revenue information
Rental revenue	14,336	12,794
Theaters
Segment revenue information
Rental revenue	13,344	13,449
Transportation services
Segment revenue information
Rental revenue	15,388	13,091
Wholesale clubs
Segment revenue information
Rental revenue	9,413	9,370
Other
Segment revenue information
Rental revenue	$ 50,909	$ 48,281