SCHEDULE III - REAL ESTATE PROPERTIES AND ACCUMULATED DEPRECIATION (Details 2) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2017
SEC Schedule III, Real Estate and Accumulated Depreciation Disclosure [Abstract]
Total real estate properties				$ 977,872
Less: Accumulated depreciation and amortization				(66,622)
Net real estate properties	$ 793,572	$ 757,027	$ 635,612	$ 911,250
Reconciliation of real estate properties
Balance at beginning of year	793,572	757,027	635,612
Additions:
Acquisitions	239,923	318,680	129,425
Capital improvements	9,298	19,649	8,442
Capitalized development expenses and carrying costs	16,069	27,194	55,623
Total additions	265,290	365,523	193,490
Deductions:
Sales	113,552	150,786	51,394
Depreciation / amortization / paydowns	30,489	24,328	20,681
Other dispositions	3,571	0	0
Reconciliation of partnership interest	0	153,864	0
Total deductions	147,612	328,978	72,075
Balance at end of year	$ 911,250	$ 793,572	$ 757,027