Significant Components of Deferred Tax Assets and Liabilities (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Deferred tax assets:
Employee benefits	$ 1,501	$ 1,590
Inventories	5,797	3,834
Goodwill	2,323	2,805
Other	4,747	2,652
Total deferred tax assets	14,368	10,881
Deferred tax liabilities:
Depreciation	35,402	28,274
Foreign earnings	644	1,509
Total deferred tax liabilities	36,046	29,783
Net deferred tax liabilities	$ 21,678	$ 18,902