Segment Information (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2024 USD ($) state region	Jun. 30, 2023 USD ($)	Jun. 30, 2024 USD ($) state region segment	Jun. 30, 2023 USD ($)	Sep. 30, 2023 USD ($)
Segment Reporting Information [Line Items]
Number of states in which home building segments operate | state	13		13
Number of regions in which entity operates | region	3		3
Number of reportable segments | segment			3
Revenue	$ 595,682	$ 572,544	$ 1,524,040	$ 1,561,380
Operating income	28,524	47,900	84,780	115,194
Gain on sale of investments	8,600		8,600
Depreciation and amortization	3,892	2,907	9,698	8,440
Capital expenditures			16,691	14,122
Assets	2,594,546		2,594,546		$ 2,411,033
Operating Segments
Segment Reporting Information [Line Items]
Operating income	67,495	88,974	180,595	219,546
Depreciation and amortization	3,411	2,573	8,377	7,506
Corporate and unallocated
Segment Reporting Information [Line Items]
Operating income	(38,971)	(41,074)	(95,815)	(104,352)
Depreciation and amortization	481	334	1,321	934
Capital expenditures			4,974	4,034
Assets	505,341		505,341		739,986
West
Segment Reporting Information [Line Items]
Revenue	369,359	328,347	953,790	933,575
West | Operating Segments
Segment Reporting Information [Line Items]
Operating income	45,582	55,629	119,951	138,499
Depreciation and amortization	2,520	1,750	6,283	5,294
Capital expenditures			9,132	6,840
Assets	1,220,127		1,220,127		994,597
East
Segment Reporting Information [Line Items]
Revenue	123,565	133,096	310,186	339,357
East | Operating Segments
Segment Reporting Information [Line Items]
Operating income	9,158	16,415	27,796	41,921
Depreciation and amortization	494	402	1,109	1,063
Capital expenditures			1,829	1,975
Assets	477,204		477,204		356,020
Southeast
Segment Reporting Information [Line Items]
Revenue	102,758	111,101	260,064	288,448
Southeast | Operating Segments
Segment Reporting Information [Line Items]
Operating income	12,755	16,930	32,848	39,126
Depreciation and amortization	397	$ 421	985	1,149
Capital expenditures			756	$ 1,273
Assets	$ 391,874		$ 391,874		$ 320,430