Debt Obligations - Schedule of Debt Obligations (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Sep. 30, 2018
Debt Obligations
Deferred mortgage costs	$ (6,646)	$ (6,735)
Total debt obligations, net of deferred costs	808,860	829,470
Mortgages payable
Debt Obligations
Total debt obligations, net of deferred costs	778,106	798,805
Deferred mortgage costs	(6,289)	(6,373)
Junior subordinated notes
Debt Obligations
Total debt obligations, net of deferred costs	37,400	37,400
Deferred mortgage costs	$ (357)	$ (362)