Accounts Payable and Accrued Liabilities (Detail) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Accounts Payable and Accrued Liabilities [Abstract]
Trade accounts payable	$ 139,833	$ 128,106
Accrued wages, salaries and employee benefits	39,442	49,871
Accrued discounts and allowances	10,714	10,291
Accrued taxes other than income taxes payable	7,287	6,946
Accrued utilities	6,474	6,712
Accrued interest	12,297	12,149
Other	8,130	9,624
Accounts payable and accrued liabilities	$ 224,177	$ 223,699