Commitments and Contingencies - Additional Information (Detail) (USD $)	3 Months Ended	6 Months Ended				6 Months Ended			6 Months Ended
	Sep. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013 Contract Termination [Member] sqft	Jun. 30, 2013 Subleases [Member] sqft	Jun. 30, 2013 Residential Use [Member]	Jun. 30, 2013 Commercial Use [Member]	Jul. 31, 2013 Subsequent Event [Member] One Sublease Expires on July 31, 2013 [Member] sqft	Jun. 30, 2013 Minimum [Member] Subleases [Member]	Jun. 30, 2013 Maximum [Member] Subleases [Member]	Jun. 30, 2013 Transcend, Enhance and Universal Fascia Product [Member] Residential Use [Member]	Jun. 30, 2013 Transcend, Enhance and Universal Fascia Product [Member] Commercial Use [Member]	Jun. 30, 2013 TrexTrim and Trex Reveal Railing [Member] Commercial and Residential Use [Member]
Commitments And Contingencies [Line Items]
Lease square feet				55,047	55,047			4,028
Expiration date of reconsidered corporate headquarters lease				Jun. 30, 2019
Expiration period of existing subleases									2014	2019
Minimum payments remaining under the Company's lease relating to its reconsidered corporate relocation for remainder of 2013				$ 800,000
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				2,800,000
Minimum receipts remaining under the Company's existing subleases for remainder of 2013				700,000
Minimum receipts remaining under the Company's existing subleases for 2014				1,600,000
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		1,487,000
Percentage change in warranty claims used as a threshold for disclosure		10.00%
Change in warranty reserve for disclosure purposes only		3,000,000
Capped cost to Trex, excluding attorneys' fees, upon final approval of the settlement by the Court		8,250,000
Capped attorneys' fees to be paid to Plaintiffs' counsel upon final approval of the settlement by the Court		1,450,000
Liability related to mold growth litigation		3,391,000
Expected total net cost to resolve the lawsuit will not exceed		$ 10,000,000