CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Income Statement [Abstract]
Total revenue	$ 781,701	$ 482,738	$ 421,260	$ 402,040	$ 767,945	$ 511,521	$ 455,178	$ 372,489	$ 2,087,739	$ 2,107,133	$ 1,916,278
Home construction and land sales expenses									1,773,085	1,755,619	1,600,969
Inventory impairments and abandonments	0	0	147,611	1,007	6,331	168	0	0	148,618	6,499	2,445
Gross profit	116,297	71,764	(82,680)	60,655	125,865	83,244	75,077	60,829	166,036	345,015	312,864
Commissions									79,802	81,002	74,811
General and administrative expenses									161,371	168,658	161,906
Depreciation and amortization									14,759	13,807	14,009
Operating (loss) income	36,005	9,543	(138,950)	3,506	43,462	17,580	13,825	6,681	(89,896)	81,548	62,138
Equity in income of unconsolidated entities									404	34	371
Loss on extinguishment of debt, net	(25,494)	358	216	0	(1,935)	0	0	(25,904)	(24,920)	(27,839)	(12,630)
Other expense, net									(2,226)	(4,305)	(15,230)
(Loss) income from continuing operations before income taxes									(116,638)	49,438	34,649
(Benefit) expense from income taxes									(37,217)	94,484	2,696
(Loss) income from continuing operations	$ 2,464	$ 11,625	$ (100,832)	$ 7,322	$ 60,484	$ 13,429	$ 11,616	$ (130,575)	(79,421)	(45,046)	31,953
Loss from discontinued operations, net of tax									(99)	(329)	(140)
Net (loss) income									$ (79,520)	$ (45,375)	$ 31,813
Weighted-average number of shares:
Basic (in shares)									30,617	32,141	31,952
Diluted (in shares)									30,617	32,141	32,426
Basic (loss) income per share:
Continuing operations (in dollars per share)	$ 0.08	$ 0.38	$ (3.28)	$ 0.23	$ 1.88	$ 0.42	$ 0.36	$ (4.07)	$ (2.59)	$ (1.40)	$ 1.00
Discontinued operations (in dollars per share)									(0.01)	(0.01)	0.00
Total (in dollars per share)									(2.60)	(1.41)	1.00
Diluted (loss) income per share:
Continuing operations (in dollars per share)	$ 0.08	$ 0.38	$ (3.28)	$ 0.23	$ 1.83	$ 0.41	$ 0.36	$ (4.07)	(2.59)	(1.40)	0.99
Discontinued operations (in dollars per share)									(0.01)	(0.01)	0.00
Total (in dollars per share)									$ (2.60)	$ (1.41)	$ 0.99