Segment Reporting (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($) segment	Jun. 30, 2016 USD ($)	Sep. 30, 2016 USD ($)
Segment Reporting [Abstract]
Number of reportable segments | segment			2
Revenues:
Rental and other revenues from real estate properties	$ 26,673	$ 23,679	$ 76,404	$ 69,991
Other income	188	608	980	2,641
Total revenues	26,861	24,287	77,384	72,632
Expenses:
Real estate operating expenses	13,283	11,986	37,638	35,177
Interest expense	7,180	6,014	20,269	17,594
Advisor’s fees, related party	0	0	0	693
Property acquisition costs	0	1,408	0	2,418
General and administrative	2,309	2,373	7,296	6,402
Depreciation	7,561	5,871	21,630	16,487
Total expenses	30,333	27,652	86,833	78,771
Total revenue less total expenses	(3,472)	(3,365)	(9,449)	(6,139)
Equity in (loss) earnings from unconsolidated joint ventures	(307)	0	(307)	0
Gain on sale of real estate	0	10,263	35,838	35,098
Loss on extinguishment of debt	0	0	(799)	(2,668)
Gain on sale of partnership interest	0	386	0	386
(Loss) income from continuing operations	(3,779)	7,284	25,283	26,677
Provision for taxes	41	0	1,499	0
(Loss) income from continuing operations	(3,820)	7,284	23,784	26,677
Net loss (income) attributable to non-controlling interests	418	(1,804)	(15,645)	(10,974)
Net income attributable to common stockholders before reconciling adjustment	(3,402)	5,480	8,139	14,044
Reconciling adjustment:
Discontinued operations, net of non-controlling interest	0	0	0	14,338
Net (loss) income attributable to common stockholders	(3,402)	5,480	8,139	28,382
Assets	979,384	788,121	979,384	788,121	$ 874,899
Multi-Family Real Estate
Revenues:
Rental and other revenues from real estate properties	26,269
Other income	0
Total revenues	26,269
Expenses:
Real estate operating expenses	13,142
Interest expense	7,054
General and administrative	2,263
Depreciation	7,532
Total expenses	29,991
(Loss) income from continuing operations	(4,053)
Provision for taxes	41
(Loss) income from continuing operations	(4,094)
Net loss (income) attributable to non-controlling interests	451
Reconciling adjustment:
Net (loss) income attributable to common stockholders	(3,643)
Assets	962,259	757,522	962,259	757,522
Other Real Estate
Revenues:
Rental and other revenues from real estate properties	404
Other income	188
Total revenues	592
Expenses:
Real estate operating expenses	141
Interest expense	126
General and administrative	46
Depreciation	29
Total expenses	342
(Loss) income from continuing operations	274
Provision for taxes	0
(Loss) income from continuing operations	274
Net loss (income) attributable to non-controlling interests	(33)
Reconciling adjustment:
Net (loss) income attributable to common stockholders	241
Assets	17,125	30,599	17,125	30,599
Operating Segments
Revenues:
Rental and other revenues from real estate properties		23,679	76,404	69,991
Other income		608	980	2,641
Total revenues		24,287	77,384	72,632
Expenses:
Real estate operating expenses		11,986	37,638	35,177
Interest expense		6,014	20,269	17,594
Advisor’s fees, related party				693
Property acquisition costs		1,408		2,418
General and administrative		2,373	7,296	6,402
Depreciation		5,871	21,630	16,487
Total expenses		27,652	86,833	78,771
Total revenue less total expenses	(3,472)	(3,365)	(9,449)	(6,139)
Equity in (loss) earnings from unconsolidated joint ventures	(307)		(307)
Gain on sale of real estate		10,263	35,838	35,098
Loss on extinguishment of debt			(799)	(2,668)
Gain on sale of partnership interest		386		386
(Loss) income from continuing operations			25,283
Provision for taxes			1,499
(Loss) income from continuing operations		7,284	23,784	26,677
Net loss (income) attributable to non-controlling interests		(1,804)	(15,645)	(10,974)
Net income attributable to common stockholders before reconciling adjustment				15,703
Reconciling adjustment:
Net (loss) income attributable to common stockholders		5,480	8,139
Operating Segments | Multi-Family Real Estate
Revenues:
Rental and other revenues from real estate properties		23,323	75,229	68,961
Other income		0	(9)	0
Total revenues		23,323	75,220	68,961
Expenses:
Real estate operating expenses		11,831	37,241	34,729
Interest expense		5,991	19,016	17,478
Advisor’s fees, related party				593
Property acquisition costs		1,408		2,418
General and administrative		2,326	7,150	6,221
Depreciation		5,844	21,547	16,407
Total expenses		27,400	84,954	77,846
Total revenue less total expenses	(3,722)	(4,077)	(9,734)	(8,885)
Equity in (loss) earnings from unconsolidated joint ventures	(331)		(331)
Gain on sale of real estate		10,263	35,389	34,489
Loss on extinguishment of debt			(799)	(2,668)
Gain on sale of partnership interest		386		386
(Loss) income from continuing operations			24,525
Provision for taxes			1,470
(Loss) income from continuing operations		6,572	23,055	23,322
Net loss (income) attributable to non-controlling interests		(1,776)	(15,544)	(12,555)
Net income attributable to common stockholders before reconciling adjustment				10,767
Reconciling adjustment:
Net (loss) income attributable to common stockholders		4,796	7,511
Operating Segments | Other Real Estate
Revenues:
Rental and other revenues from real estate properties		356	1,175	1,030
Other income		608	989	2,641
Total revenues		964	2,164	3,671
Expenses:
Real estate operating expenses		155	397	448
Interest expense		23	1,253	116
Advisor’s fees, related party				100
Property acquisition costs		0		0
General and administrative		47	146	181
Depreciation		27	83	80
Total expenses		252	1,879	925
Total revenue less total expenses	250	712	285	2,746
Equity in (loss) earnings from unconsolidated joint ventures	$ 24		24
Gain on sale of real estate		0	449	609
Loss on extinguishment of debt			0	0
Gain on sale of partnership interest		0
(Loss) income from continuing operations			758
Provision for taxes			29
(Loss) income from continuing operations		712	729	3,355
Net loss (income) attributable to non-controlling interests		(28)	(101)	1,581
Net income attributable to common stockholders before reconciling adjustment				4,936
Reconciling adjustment:
Net (loss) income attributable to common stockholders		$ 684	$ 628
Segment Reconciling Items
Reconciling adjustment:
Discontinued operations, net of non-controlling interest				$ 12,679