Other Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Initial direct costs	$ 28,319	$ 29,979
Internal-use software	17,782	17,477
Prepaid expense	10,420	6,770
Corporate furniture, fixtures and equipment	5,860	6,408
Deferred financing costs - revolving credit facility	796	957
Other	2,348	1,872
Total	106,813	103,501
ASU 2016-02
Deferred rent receivable	$ 41,288	$ 40,038