Commitments - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended				12 Months Ended				1 Months Ended	12 Months Ended		1 Months Ended		12 Months Ended			1 Months Ended		12 Months Ended				1 Months Ended	12 Months Ended					1 Months Ended	12 Months Ended			1 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013 Lease Agreements	Dec. 31, 2013 During 2014 Natural Gas Purchase Contract	Dec. 31, 2013 During 2015 Natural Gas Purchase Contract	Dec. 31, 2013 During 2016 Natural Gas Purchase Contract	Dec. 31, 2013 During 2017 Natural Gas Purchase Contract	Oct. 31, 2008 Bauxite raw materials Supplier 4	Dec. 31, 2012 Bauxite raw materials Supplier 4	Dec. 31, 2011 Bauxite raw materials Supplier 4	Oct. 31, 2008 Bauxite raw materials Supplier 4 Within Three Years From Agreement Date T	Oct. 31, 2008 Bauxite raw materials Supplier 4 More Than Three Years From Agreement Date T	Dec. 31, 2011 Hard Clays Supplier 6 CHINA	Dec. 31, 2002 Hard Clays Supplier 6 CHINA	Dec. 31, 2002 Hard Clays Supplier 6 Minimum CHINA	Nov. 01, 2008 McIntyre Wilkinson County Development Authority	Jan. 31, 2003 McIntyre kaolin Supplier 3	Dec. 31, 2013 McIntyre kaolin Supplier 3	Dec. 31, 2012 McIntyre kaolin Supplier 3	Dec. 31, 2011 McIntyre kaolin Supplier 3	Jan. 31, 2003 McIntyre kaolin Supplier 3 Minimum	May 31, 2012 Eufaula kaolin Supplier 2	Dec. 31, 2013 Eufaula kaolin Supplier 2	Dec. 31, 2012 Eufaula kaolin Supplier 2	Dec. 31, 2011 Eufaula kaolin Supplier 2	May 31, 2012 Eufaula kaolin Supplier 2 After Amendment	Dec. 31, 2011 Eufaula kaolin Supplier 2 Minimum	May 31, 2012 Eufaula kaolin Supplier 2 Minimum After Amendment	Dec. 31, 2013 Marshfield, Wisconsin	Dec. 31, 2012 Marshfield, Wisconsin	Dec. 31, 2011 Marshfield, Wisconsin	Jul. 31, 2011 Marshfield, Wisconsin Prior Agreement	Jan. 30, 2012 Marshfield, Wisconsin After Amendment	Jan. 30, 2012 Marshfield, Wisconsin During 2013 After Amendment T	Jan. 30, 2012 Marshfield, Wisconsin During 2014 After Amendment T	Jul. 31, 2011 Marshfield, Wisconsin During 2011 Prior Agreement T	Jul. 31, 2011 Marshfield, Wisconsin During 2012 Prior Agreement T	Jan. 30, 2012 Marshfield, Wisconsin During 2012 After Amendment T	Nov. 30, 2012 Millen Georgia Jenkins County Development Authority	May 31, 2012 Millen Georgia Kaolin And Bauxite Supplier 7	May 31, 2012 Millen Georgia Kaolin And Bauxite Supplier 7 Minimum
Long-term Purchase Commitment [Line Items]
Commitment effective date																		2003-01-01					May 2012			2011-01-01							2011-07-30
Purchase commitment, period									10 years						10 years											3 years			5 years				5 years								5 years
Additional purchase commitment, period									10 years																	6 years	3 years														5 years
Purchase obligation percentage of annual requirements																80.00%						80.00%						70.00%	50.00%													50.00%
Purchase commitment amount											$ 1,400			$ 2,918					$ 1,381	$ 2,491	$ 2,900			$ 3,788	$ 3,012	$ 3,205				$ 3,546	$ 2,538	$ 462
Agreement entry date									Oct. 31, 2008								Nov. 01, 2008	Jan. 01, 2003																						Nov. 01, 2012	May 31, 2012
Minimum quantity to be purchased annually												40,000	70,000																						150,000	350,000	40,000	100,000	150,000
Purchase commitment coverage period													3 years
Agreement Termination Date										2012
Agreement expiration date														Dec. 31, 2011
Purchase commitment, commencing date																																		2012-01-30
Facility construction completion period																																									Construction of the facility is expected to be completed in early 2014.
Annual rental fee	22,542	21,452	11,590														50
Lease agreement period																	Through the year 2022																							Until the tenth anniversary of completion of the final phase of the facility
Lease administrative fees																																								50
Net book value of property leased	478,535	426,232		292,190
Natural gas purchase commitment annually					$ 21,010	$ 21,009	$ 13,949	$ 3,551