Accounts Payable and Accrued Expenses - Components of Accounts Payable and Accrued Expenses (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Payables and Accruals [Abstract]
Accounts payable	$ 424,140	$ 416,847
Payroll and benefits, including incentive compensation	62,551	101,315
Health insurance, workers’ compensation and other insurance costs	60,068	60,357
Customer rebates	38,571	41,919
Other accrued liabilities	85,740	86,543
Total	$ 671,070	$ 706,981