Other Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Other Assets.
Deferred rent receivable	$ 38,943	$ 43,162
Initial direct costs	26,891	24,651
Internal-use software	17,033	17,708
Prepaid expense	9,117	7,090
Corporate furniture, fixtures and equipment	4,829	5,006
Deferred financing costs - revolving credit facility	2,241	2,880
Other	3,878	1,793
Total	$ 102,932	$ 102,290