Commitments and Contingencies - Additional Information (Detail) (USD $)	0 Months Ended	3 Months Ended
	Sep. 03, 2013 Lawsuits	Mar. 31, 2014	Dec. 31, 2013
Schedule Of Commitments And Contingencies [Line Items]
Charge recorded due to revised estimate of sublease receipts		$ 567,000
Percentage change in warranty claims used as a threshold for disclosure		10.00%
Change in warranty reserve for disclosure purposes only		3,900,000
Number of lawsuits settled	2
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
Payments related to mold growth litigation		1,600,000
Remaining accrual related to litigation		1,586,000	3,174,000
Expected total net cost to resolve the lawsuit will not exceed		10,000,000
Residential Use [Member]
Schedule Of Commitments And Contingencies [Line Items]
Warranty period		25 years
Commercial Use [Member]
Schedule Of Commitments And Contingencies [Line Items]
Warranty period		10 years
Transcend, Enhance, Select and Universal Fascia Product [Member] | Residential Use [Member]
Schedule Of Commitments And Contingencies [Line Items]
Warranty period		25 years
Transcend, Enhance, Select and Universal Fascia Product [Member] | Commercial Use [Member]
Schedule Of Commitments And Contingencies [Line Items]
Warranty period		10 years
TrexTrim and Trex Reveal Railing [Member] | Commercial and Residential Use [Member]
Schedule Of Commitments And Contingencies [Line Items]
Warranty period		25 years
Contract Termination [Member]
Schedule Of Commitments And Contingencies [Line Items]
Lease square feet		55,047
Charge recorded due to revised estimate of sublease receipts		600,000
Minimum payments remaining under the Company's lease relating to its reconsidered corporate relocation for remainder of 2014		1,300,000
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 for 2018		1,800,000
Minimum payments remaining under the Company's lease relating to its reconsidered corporate relocation, thereafter		900,000
Minimum receipts remaining under the Company's existing subleases for remainder of 2014		1,000,000
Minimum receipts remaining under the Company's existing subleases for 2015		800,000
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 for 2018		700,000
Minimum receipts remaining under the Company's existing subleases, thereafter		$ 400,000
Sublease [Member]
Schedule Of Commitments And Contingencies [Line Items]
Lease square feet		41,701
Subleases Expiring December 31, 2014 Member [Member]
Schedule Of Commitments And Contingencies [Line Items]
Lease square feet		16,969