CONSOLIDATED STATEMENTS OF INCOME - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
Revenue:
Total revenue	$ 272,717	$ 243,294	$ 179,725	$ 199,597	$ 245,921	$ 223,399	$ 156,512	$ 165,615	$ 895,333	$ 791,447	$ 702,576
Cost of revenue:
Total cost of revenue									625,442	565,754	510,094
Gross profit	90,301	76,762	47,141	55,687	78,577	67,672	38,551	40,893	269,891	225,693	192,482
Operating expenses:
Selling, general and administrative									149,623	137,650	117,841
Amortization									18,161	21,319	20,230
Total operating expenses									167,784	158,969	138,071
Operating income									102,107	66,724	54,411
Other income (expense):
Net interest expense									(64,219)	(46,329)	(42,566)
Other, net									(218)	(348)	364
Total other income (expense), net									(64,437)	(46,677)	(42,202)
Income from continuing operations before income taxes									37,670	20,047	12,209
Income tax benefit (provision)	(96,800)								94,458	(3,574)	(3,924)
Income from continuing operations									132,128	16,473	8,285
Loss from discontinued operations, net of income taxes									(460)	(415)	(1,148)
Net income	$ 126,774	$ 23,008	$ (25,198)	$ 7,084	$ 16,681	$ 10,893	$ (10,082)	$ (1,434)	131,668	16,058	7,137
Net income attributable to non-controlling interest									(869)	(774)	0
Net income attributable to Headwaters Incorporated									$ 130,799	$ 15,284	$ 7,137
Basic income (loss) per share attributable to Headwaters Incorporated:
From continuing operations (in dollars per share)									$ 1.79	$ 0.21	$ 0.12
From discontinued operations (in dollars per share)									(0.01)	(0.01)	(0.02)
Basic income (loss) per share (in dollars per share)	$ 1.72	$ 0.30	$ (0.34)	$ 0.09					1.78	0.20	0.10
Diluted income (loss) per share attributable to Headwaters Incorporated:
From continuing operations (in dollars per share)									1.74	0.21	0.12
From discontinued operations (in dollars per share)									(0.01)	(0.01)	(0.02)
Diluted income (loss) per share (in dollars per share)	$ 1.68	$ 0.30	$ (0.34)	$ 0.09					$ 1.73	$ 0.20	$ 0.10
Building products
Revenue:
Total revenue									$ 523,643	$ 472,434	$ 394,324
Cost of revenue:
Total cost of revenue									367,163	336,283	283,128
Construction materials
Revenue:
Total revenue									352,263	309,337	293,000
Cost of revenue:
Total cost of revenue									249,077	224,888	219,996
Energy Technology
Revenue:
Total revenue									19,427	9,676	15,252
Cost of revenue:
Total cost of revenue									$ 9,202	$ 4,583	$ 6,970