Other Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Other Assets.
Deferred rent receivable	$ 42,705	$ 40,038
Initial direct costs	27,299	29,979
Internal-use software	17,665	17,477
Prepaid expense	6,745	6,770
Corporate furniture, fixtures and equipment	5,686	6,408
Deferred financing costs - revolving credit facility	3,311	957
Other	2,776	1,872
Total	$ 106,187	$ 103,501