Operating Segments and Related Disclosures - Selected Financial Information for Each Reportable Segment, Components of Assets (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Assets	$ 2,899.9	$ 2,707.8
Operating Segments
Segment Reporting Information [Line Items]
Assets	1,618.8	1,647.9
Operating Segments | Aerospace and Defense
Segment Reporting Information [Line Items]
Assets	1,484.9	1,515.1
Operating Segments | Real Estate Segment
Segment Reporting Information [Line Items]
Assets	133.9	132.8
Corporate
Segment Reporting Information [Line Items]
Assets	$ 1,281.1	$ 1,059.9