Acquisitions and Discontinued Operations - Transformers Solutions Business - Assets and Liabilities of Discontinued Operations (Details) - Discontinued operations, disposed of by sale - Transformer Solutions $ in Millions	Dec. 31, 2020 USD ($)
ASSETS
Accounts receivable, net	$ 50.9
Contract assets	48.6
Inventories, net	21.7
Other current assets	3.2
Property, plant and equipment:
Property, plant and equipment, gross	210.7
Accumulated depreciation	(131.0)
Property, plant and equipment, net	79.7
Goodwill	131.3
Other assets	8.1
Total assets - discontinued operations	343.5
LIABILITIES
Accounts payable	34.1
Contract liabilities	57.2
Accrued expenses	24.5
Deferred and other income taxes	22.3
Other long-term liabilities	9.1
Total liabilities - discontinued operations	147.2
Land
Property, plant and equipment:
Property, plant and equipment, gross	6.5
Buildings and leasehold improvements
Property, plant and equipment:
Property, plant and equipment, gross	63.1
Machinery and equipment
Property, plant and equipment:
Property, plant and equipment, gross	$ 141.1