Long-Term Debt - Additional information (Detail) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Debt Instrument [Line Items]
Maximum consolidated debt reduction for unrestricted cash and cash equivalents for debt covenant calculation			$ 200,000,000
Additional interest expense	$ 318,000	$ 300,000	942,000	$ 883,000
Maximum | Texas Industries Inc.
Debt Instrument [Line Items]
Amendment consolidated EBITDA					$ 95,000,000
Acquisition integration expenses					70,000,000
Minimum
Debt Instrument [Line Items]
Reduction of consolidated debt in the debt ratio calculation			$ 50,000,000
Including Acquisition Bridge Debt | Maximum
Debt Instrument [Line Items]
Debt covenant	3.50		3.50
Excluding Acquisition Bridge Debt | Maximum
Debt Instrument [Line Items]
Debt covenant	3.75		3.75
Trade Receivable Facility
Debt Instrument [Line Items]
Credit facility commitment	$ 250,000,000		$ 250,000,000
Debt instrument maturity period			Sep. 30, 2016
Eligible trade receivables	517,404,000	477,535,000	$ 517,404,000	477,535,000	369,575,000
Credit facility borrowing base	425,733,000	405,904,000	425,733,000	405,904,000	313,428,000
Term Loan Facility
Debt Instrument [Line Items]
Credit facility commitment	250,000,000		250,000,000
Revolving Facility
Debt Instrument [Line Items]
Credit facility commitment	350,000,000		$ 350,000,000
Senior unsecured revolving facility, maturity period			5 years
Outstanding letters of credit	$ 2,507,000	$ 2,507,000	$ 2,507,000	$ 2,507,000	$ 2,507,000
6.6% Senior Notes, Due 2018
Debt Instrument [Line Items]
Increase in annual interest expense due to ongoing amortization of the terminated value of the swap agreements			$ 1,200,000
Interest rate on notes	6.60%		6.60%
Maturity date			2018
London Interbank Offered Rate(LIBOR) | Trade Receivable Facility
Debt Instrument [Line Items]
Basis spread on variable rate			0.70%