Condensed Consolidating Financial Information - Statements of Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Revenue:
Revenue	$ 262,466	$ 243,294	$ 683,216	$ 622,616
Cost of revenue:
Total cost of revenue	178,935	166,532	480,537	443,026
Gross profit	83,531	76,762	202,679	179,590
Operating expenses:
Selling, general and administrative	42,408	38,906	115,172	105,286
Amortization	5,029	4,557	14,410	13,603
Total operating expenses	47,437	43,463	129,582	118,889
Operating income (loss)	36,094	33,299	73,097	60,701
Other income (expense):
Net interest expense	(9,270)	(8,083)	(25,543)	(56,000)
Equity in earnings of subsidiaries			0	0
Other, net	(207)	122	(288)	(180)
Total other income (expense), net	(9,477)	(7,961)	(25,831)	(56,180)
Income (loss) from continuing operations before income taxes	26,617	25,338	47,266	4,521
Income tax benefit (provision)	(9,090)	(2,220)	(14,190)	760
Income from continuing operations	17,527	23,118	33,076	5,281
Income (loss) from discontinued operations, net of income taxes	258	(110)	(186)	(387)
Net income	17,785	23,008	32,890	4,894
Net income attributable to non-controlling interest	(269)	(191)	(848)	(695)
Net income attributable to Headwaters Incorporated	17,516	22,817	32,042	4,199
Building products
Revenue:
Revenue	162,642	147,830	423,682	371,770
Cost of revenue:
Total cost of revenue	111,409	100,801	297,742	264,474
Construction materials
Revenue:
Revenue	97,741	91,900	255,494	240,802
Cost of revenue:
Total cost of revenue	66,577	63,850	181,059	174,099
Energy technology
Revenue:
Revenue	2,083	3,564	4,040	10,044
Cost of revenue:
Total cost of revenue	949	1,881	1,736	4,453
Consolidation, Eliminations
Other income (expense):
Equity in earnings of subsidiaries	(27,113)	(34,508)	(56,760)	(68,633)
Total other income (expense), net	(27,113)	(34,508)	(56,760)	(68,633)
Income (loss) from continuing operations before income taxes	(27,113)	(34,508)	(56,760)	(68,633)
Income from continuing operations	(27,113)	(34,508)	(56,760)	(68,633)
Net income	(27,113)	(34,508)	(56,760)	(68,633)
Net income attributable to Headwaters Incorporated	(27,113)	(34,508)	(56,760)	(68,633)
Guarantor Subsidiaries
Revenue:
Revenue	245,459	231,581	641,596	589,291
Cost of revenue:
Total cost of revenue	166,575	158,019	450,920	419,774
Gross profit	78,884	73,562	190,676	169,517
Operating expenses:
Selling, general and administrative	31,712	30,296	88,737	82,734
Amortization	4,661	4,189	13,305	12,498
Total operating expenses	36,373	34,485	102,042	95,232
Operating income (loss)	42,511	39,077	88,634	74,285
Other income (expense):
Net interest expense	(101)	(25)	(196)	(129)
Other, net	(220)	130	(345)	(12)
Total other income (expense), net	(321)	105	(541)	(141)
Income (loss) from continuing operations before income taxes	42,190	39,182	88,093	74,144
Income tax benefit (provision)	(16,200)	(5,430)	(33,330)	(8,000)
Income from continuing operations	25,990	33,752	54,763	66,144
Income (loss) from discontinued operations, net of income taxes				(67)
Net income	25,990	33,752	54,763	66,077
Net income attributable to Headwaters Incorporated	25,990	33,752	54,763	66,077
Guarantor Subsidiaries | Building products
Revenue:
Revenue	145,635	136,117	382,062	338,445
Cost of revenue:
Total cost of revenue	99,049	92,288	268,125	241,222
Guarantor Subsidiaries | Construction materials
Revenue:
Revenue	97,741	91,900	255,494	240,802
Cost of revenue:
Total cost of revenue	66,577	63,850	181,059	174,099
Guarantor Subsidiaries | Energy technology
Revenue:
Revenue	2,083	3,564	4,040	10,044
Cost of revenue:
Total cost of revenue	949	1,881	1,736	4,453
Non-Guarantor Subsidiaries
Revenue:
Revenue	17,007	11,713	41,620	33,325
Cost of revenue:
Total cost of revenue	12,360	8,513	29,617	23,252
Gross profit	4,647	3,200	12,003	10,073
Operating expenses:
Selling, general and administrative	2,348	1,637	5,901	4,829
Amortization	368	368	1,105	1,105
Total operating expenses	2,716	2,005	7,006	5,934
Operating income (loss)	1,931	1,195	4,997	4,139
Other income (expense):
Net interest expense	(30)		(33)
Other, net	13	(8)	57	(168)
Total other income (expense), net	(17)	(8)	24	(168)
Income (loss) from continuing operations before income taxes	1,914	1,187	5,021	3,971
Income tax benefit (provision)	(780)	(130)	(1,990)	(400)
Income from continuing operations	1,134	1,057	3,031	3,571
Income (loss) from discontinued operations, net of income taxes	258	(110)	(186)	(320)
Net income	1,392	947	2,845	3,251
Net income attributable to non-controlling interest	(269)	(191)	(848)	(695)
Net income attributable to Headwaters Incorporated	1,123	756	1,997	2,556
Non-Guarantor Subsidiaries | Building products
Revenue:
Revenue	17,007	11,713	41,620	33,325
Cost of revenue:
Total cost of revenue	12,360	8,513	29,617	23,252
Parent Company
Operating expenses:
Selling, general and administrative	8,348	6,973	20,534	17,723
Total operating expenses	8,348	6,973	20,534	17,723
Operating income (loss)	(8,348)	(6,973)	(20,534)	(17,723)
Other income (expense):
Net interest expense	(9,139)	(8,058)	(25,314)	(55,871)
Equity in earnings of subsidiaries	27,113	34,508	56,760	68,633
Total other income (expense), net	17,974	26,450	31,446	12,762
Income (loss) from continuing operations before income taxes	9,626	19,477	10,912	(4,961)
Income tax benefit (provision)	7,890	3,340	21,130	9,160
Income from continuing operations	17,516	22,817	32,042	4,199
Net income	17,516	22,817	32,042	4,199
Net income attributable to Headwaters Incorporated	$ 17,516	$ 22,817	$ 32,042	$ 4,199