Inventories (Details) (USD $)
In Thousands, unless otherwise specified
Mar. 31, 2015
Dec. 31, 2014
Net Components of Inventory    
Raw materials $ 427,937 $ 352,928
Work in process 748,713 687,343
Finished goods 265,807 265,439
Less: Progress billings (245,418) (230,058)
Less: Excess and obsolete reserve (78,099) (80,088)
Inventories, net $ 1,118,940 $ 995,564