Commitments and Contingencies - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended			9 Months Ended			9 Months Ended
	Sep. 30, 2013 Letter	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Jun. 30, 2013 Subleases [Member] sqft	Sep. 30, 2013 Contract Termination [Member] sqft	Jul. 31, 2013 One Sublease Expired on July 31, 2013 [Member] sqft	Sep. 30, 2013 One Sublease in Default [Member] sqft	Sep. 30, 2013 Residential Use [Member]	Sep. 30, 2013 Commercial Use [Member]	Sep. 30, 2013 Transcend, Enhance, Select and Universal Fascia Product [Member] Residential Use [Member]	Sep. 30, 2013 Transcend, Enhance, Select and Universal Fascia Product [Member] Commercial Use [Member]	Sep. 30, 2013 TrexTrim and Trex Reveal Railing [Member] Commercial and Residential Use [Member]
Schedule Of Commitments And Contingencies [Line Items]
Lease square feet					55,047	55,047	4,028	30,315
Expiration date of reconsidered corporate headquarters lease						Jun. 30, 2019
Charge recorded due to revised estimate of sublease receipts	$ 1,100,000		$ 1,144,000	$ 127,000
Minimum payments remaining under the Company's lease relating to its reconsidered corporate relocation for remainder of 2013						400,000
Minimum payments remaining under the Company's lease relating to its reconsidered corporate relocation for 2014						1,700,000
Minimum payments remaining under the Company's lease relating to its reconsidered corporate relocation for 2015						1,700,000
Minimum payments remaining under the Company's lease relating to its reconsidered corporate relocation for 2016						1,800,000
Minimum payments remaining under the Company's lease relating to its reconsidered corporate relocation for 2017						1,800,000
Minimum payments remaining under the Company's lease relating to its reconsidered corporate relocation, thereafter						2,700,000
Minimum receipts remaining under the Company's existing subleases for remainder of 2013						100,000
Minimum receipts remaining under the Company's existing subleases for 2014						600,000
Minimum receipts remaining under the Company's existing subleases for 2015						700,000
Minimum receipts remaining under the Company's existing subleases for 2016						700,000
Minimum receipts remaining under the Company's existing subleases for 2017						700,000
Minimum receipts remaining under the Company's existing subleases, thereafter						1,100,000
Warranty period									25 years	10 years	25 years	10 years	25 years
Increase in warranty reserve	20,000,000	20,000,000	20,000,000	21,487,000
Letters sent to homeowners	10,000
Percentage change in warranty claims used as a threshold for disclosure			10.00%
Change in warranty reserve for disclosure purposes only	4,300,000		4,300,000
Capped cost to Trex, excluding attorneys' fees, upon final approval of the settlement by the Court	8,250,000		8,250,000
Capped attorneys' fees to be paid to Plaintiffs' counsel upon final approval of the settlement by the Court	1,450,000		1,450,000
Liability related to mold growth litigation	3,300,000		3,300,000
Expected total net cost to resolve the lawsuit will not exceed	$ 10,000,000		$ 10,000,000