Summary of Inventories (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Schedule of Inventory [Line Items]
Raw materials and supplies	$ 84,545	$ 72,067
Work in process	67,132	79,982
Finished goods	13,031	13,433
Inventory, Gross, Total	164,708	165,482
Less progress payments	16,390	10,979
Total	$ 148,318	$ 154,503