Summary of Inventories (Detail) (USD $) In Thousands, unless otherwise specified	9 Months Ended	12 Months Ended
	Sep. 30, 2013	Dec. 31, 2012
Inventory, Net [Abstract]
Raw materials	$ 13,940	$ 12,501
Work in process	17,832	12,800
Finished goods	9,621	10,549
Inventory, Gross, Total	41,393	35,850
Less: Progress billings	(2,817)	(4,558)
Total inventories	$ 38,576	$ 31,292