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Stock-Based Compensation - Summary of Stock-Based Compensation Expense (Detail) (USD $)
In Thousands, unless otherwise specified
 3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Stock-based compensation expense $ 1,454us-gaap_ShareBasedCompensation $ 1,170us-gaap_ShareBasedCompensation
Time-Based Restricted Stock [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Stock-based compensation expense 833us-gaap_ShareBasedCompensation
/ us-gaap_AwardTypeAxis
= trex_TimeBasedRestrictedStockMember		 708us-gaap_ShareBasedCompensation
/ us-gaap_AwardTypeAxis
= trex_TimeBasedRestrictedStockMember
Performance-Based Restricted Stock [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Stock-based compensation expense 399us-gaap_ShareBasedCompensation
/ us-gaap_AwardTypeAxis
= trex_PerformanceBasedRestrictedStockMember		 82us-gaap_ShareBasedCompensation
/ us-gaap_AwardTypeAxis
= trex_PerformanceBasedRestrictedStockMember
Stock Appreciation Rights [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Stock-based compensation expense 189us-gaap_ShareBasedCompensation
/ us-gaap_AwardTypeAxis
= us-gaap_StockAppreciationRightsSARSMember		 370us-gaap_ShareBasedCompensation
/ us-gaap_AwardTypeAxis
= us-gaap_StockAppreciationRightsSARSMember
Employee Stock Purchase Plan [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Stock-based compensation expense $ 33us-gaap_ShareBasedCompensation
/ us-gaap_AwardTypeAxis
= trex_EmployeeStockPurchasePlanMember		 $ 10us-gaap_ShareBasedCompensation
/ us-gaap_AwardTypeAxis
= trex_EmployeeStockPurchasePlanMember