Revenue - Sales by Product Category (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Entity Wide Information Revenue From External Customer [Line Items]
Net sales	$ 1,904,523	$ 2,089,888	$ 3,535,823	$ 3,790,324
Lumber and Lumber Sheet Goods
Entity Wide Information Revenue From External Customer [Line Items]
Net sales	601,487	811,159	1,119,176	1,455,068
Manufactured Products
Entity Wide Information Revenue From External Customer [Line Items]
Net sales	374,299	370,891	691,651	665,069
Windows, Doors and Millwork
Entity Wide Information Revenue From External Customer [Line Items]
Net sales	391,049	375,515	744,439	707,667
Gypsum, Roofing and Insulation
Entity Wide Information Revenue From External Customer [Line Items]
Net sales	138,388	141,273	259,307	254,149
Siding, Metal and Concrete Products
Entity Wide Information Revenue From External Customer [Line Items]
Net sales	191,289	189,536	341,207	331,699
Other Building Products and Services
Entity Wide Information Revenue From External Customer [Line Items]
Net sales	$ 208,011	$ 201,514	$ 380,043	$ 376,672