Acquisitions - Purchase Price Allocation (Details) $ in Millions	Oct. 27, 2018 USD ($)
2019 Acquisitions
Business Acquisition [Line Items]
Accounts receivable	$ 5.6
Costs and estimated earnings in excess of billings	0.0
Inventories and other current assets	0.2
Property and equipment	0.5
Goodwill	4.0
Total assets	22.6
Accounts payable	2.2
Accrued and other current liabilities	0.0
Deferred tax liabilities, net non-current	0.0
Total liabilities	2.2
Net Assets Acquired	20.4
2019 Acquisitions | Customer relationships
Business Acquisition [Line Items]
Intangible assets	12.3
2019 Acquisitions | Trade names
Business Acquisition [Line Items]
Intangible assets	0.0
2017 Acquisitions
Business Acquisition [Line Items]
Accounts receivable	8.9
Costs and estimated earnings in excess of billings	2.4
Inventories and other current assets	0.2
Property and equipment	5.6
Goodwill	10.1
Total assets	37.7
Accounts payable	3.2
Accrued and other current liabilities	3.4
Deferred tax liabilities, net non-current	5.0
Total liabilities	11.6
Net Assets Acquired	26.1
2017 Acquisitions | Customer relationships
Business Acquisition [Line Items]
Intangible assets	9.8
2017 Acquisitions | Trade names
Business Acquisition [Line Items]
Intangible assets	$ 0.7