Property and Business Interruption Insurance Claims and Recoveries - Additional Information (Detail) (USD $)	3 Months Ended				9 Months Ended
	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2013
Property And Or Business Interruption Insurance Claims [Line Items]
Deferred gain on insurance recovery	$ 25,417,000				$ 25,417,000
Insurance claim receivable	2,602,000			10,059,000	2,602,000
El Dorado Facility [Member]
Property And Or Business Interruption Insurance Claims [Line Items]
Insurance payments received with reservation of rights					40,000,000
Approved insurance payments					60,000,000
El Dorado Facility [Member] | Property Insurance [Member]
Property And Or Business Interruption Insurance Claims [Line Items]
Deductible property damage under insurance					1,000,000
Approved insurance payments					48,000,000
Insurance claim recoverable costs					24,600,000
Deferred gain on insurance recovery	23,400,000				23,400,000
El Dorado Facility [Member] | Business Interruption Insurance [Member]
Property And Or Business Interruption Insurance Claims [Line Items]
Waiting period for business interruption coverage					30 days
Approved insurance payments					12,000,000
Insurance claim receivable	700,000				700,000
El Dorado Facility [Member] | Business Interruption Insurance [Member] | Cost of sales [Member]
Property And Or Business Interruption Insurance Claims [Line Items]
Insurance claim recoverable costs	4,200,000	500,000	700,000	7,300,000	12,700,000
Cherokee Facility [Member] | Property Insurance [Member]
Property And Or Business Interruption Insurance Claims [Line Items]
Deductible property damage under insurance					2,500,000
Cherokee Facility [Member] | Business Interruption Insurance [Member]
Property And Or Business Interruption Insurance Claims [Line Items]
Waiting period for business interruption coverage					30 days
Insurance payments received with reservation of rights					15,000,000
Deferred gain on insurance recovery	2,000,000				2,000,000
Insurance claim receivable	1,900,000				1,900,000
Cherokee Facility [Member] | Business Interruption Insurance [Member] | Cost of sales [Member]
Property And Or Business Interruption Insurance Claims [Line Items]
Insurance claim recoverable costs		$ 2,900,000	$ 10,100,000		$ 13,000,000