Segment Information - Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Segment revenue information
Rental (including reimbursable)	$ 2,064,958	$ 1,639,533	$ 1,484,818
Other	15,505	7,554	3,345
Total revenue	2,080,463	1,647,087	1,488,163
Automotive service
Segment revenue information
Rental (including reimbursable)	47,830	35,090	32,365
Beverages
Segment revenue information
Rental (including reimbursable)	37,284	32,771	31,807
Child care
Segment revenue information
Rental (including reimbursable)	36,425	35,643	31,749
Convenience stores - U.S.
Segment revenue information
Rental (including reimbursable)	217,175	189,658	166,755
Dollar stores
Segment revenue information
Rental (including reimbursable)	149,136	126,719	102,695
Drug stores
Segment revenue information
Rental (including reimbursable)	153,174	140,993	127,853
Financial services
Segment revenue information
Rental (including reimbursable)	36,831	30,531	30,189
General merchandise - U.S.
Segment revenue information
Rental (including reimbursable)	72,442	49,352	35,366
Grocery stores - U.S.
Segment revenue information
Rental (including reimbursable)	88,360	78,106	69,691
Grocery stores - U.K.
Segment revenue information
Rental (including reimbursable)	100,500	51,459	17,819
Health and fitness
Segment revenue information
Rental (including reimbursable)	115,878	104,744	105,896
Health care - U.S.
Segment revenue information
Rental (including reimbursable)	33,579	25,563	21,011
Home furnishings - U.S.
Segment revenue information
Rental (including reimbursable)	21,457	12,447	10,490
Home improvement - U.S.
Segment revenue information
Rental (including reimbursable)	62,076	46,392	42,351
Home improvement - U.K.
Segment revenue information
Rental (including reimbursable)	34,470	4,224	0
Restaurants - casual dining
Segment revenue information
Rental (including reimbursable)	71,338	46,265	45,238
Restaurants - quick service- U.S.
Segment revenue information
Rental (including reimbursable)	115,758	88,163	92,018
Theaters - U.S.
Segment revenue information
Rental (including reimbursable)	90,792	78,653	87,698
Transportation services
Segment revenue information
Rental (including reimbursable)	71,955	64,131	66,500
Wholesale club
Segment revenue information
Rental (including reimbursable)	46,061	38,713	38,117
Other non-reportable segments and contractually obligated reimbursements by our clients
Segment revenue information
Rental (including reimbursable)	$ 462,437	$ 359,916	$ 329,210