Accounts Payable and Accrued Liabilities (Detail) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Accounts Payable and Accrued Liabilities [Abstract]
Trade accounts payable	$ 111,157	$ 128,045
Accrued wages, salaries and employee benefits	42,853	43,997
Accrued discounts and allowances	8,911	8,954
Accrued taxes other than income taxes payable	5,891	5,112
Accrued utilities	4,659	7,536
Accrued interest	4,848	11,981
Other	14,501	14,743
Accounts payable and accrued liabilities	$ 192,820	$ 220,368