Inventoried Costs (Details) - USD ($) $ in Millions	Sep. 27, 2015	Dec. 28, 2014
Inventory Disclosure [Abstract]
Raw materials	$ 30.4	$ 30.1
Work in process	23.3	13.3
Finished goods	2.6	2.8
Supplies and other	1.6	2.1
Subtotal inventoried costs	57.9	48.3
Less: Customer advances and progress payments	(3.3)	(0.9)
Total inventoried costs	$ 54.6	$ 47.4