Debt Obligations - Schedule of Debt Obligations (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Sep. 30, 2017
Debt Obligations
Deferred mortgage costs	$ (6,597)	$ (6,727)
Total debt obligations, net of deferred costs	749,084	734,844
Mortgages payable
Debt Obligations
Total debt obligations, net of deferred costs	718,281	704,171
Deferred mortgage costs	(6,220)	(6,345)
Junior subordinated notes
Debt Obligations
Total debt obligations, net of deferred costs	37,400	37,400
Deferred mortgage costs	$ (377)	$ (382)