Inventories - Other Inventory Information (Details) $ in Millions	Sep. 30, 2016 USD ($)	Dec. 31, 2015 USD ($)
Remaining A-10 shipsets	15
K-MAX®
Inventory noncurrent	$ 15.4	$ 14.9
SH 2GA Super Seasprite Program [Member]
Inventory gross	7.6	$ 9.0
SH 2 inventory
Inventory noncurrent	3.8
A-10 program
Backlog	7.1
Inventory gross	$ 12.7
Delivered shipsets	158
Shipsets under program of record	242
Nonrecurring costs [Member] | A-10 program
Inventory gross	$ 8.8