Acquisitions - Purchase Price Allocation (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Acquisitions 2017
Business Acquisition [Line Items]
Cash paid for acquisition of businesses	$ 87.6
Non-monetary consideration	4.3
Estimated purchase price	91.9
Assets acquired:
Property and equipment	10.3
Goodwill and identifiable intangible assets	79.8
Other current and long-term assets	8.8
Liabilities assumed:
Long-term liabilities and deferred tax liabilities	(7.0)
Estimated purchase price	$ 91.9
Acquisitions 2016
Business Acquisition [Line Items]
Cash paid for acquisition of businesses		$ 253.7
Amounts due to sellers		10.4
Estimated purchase price		264.0
Assets acquired:
Accounts and notes receivable		60.4
Inventories		35.4
Property and equipment		45.3
Goodwill and identifiable intangible assets		166.5
Other current and long-term assets		11.5
Liabilities assumed:
Accounts payable		(33.0)
Accrued expenses and other current liabilities		(21.4)
Long-term liabilities and deferred tax liabilities		(0.5)
Estimated purchase price		$ 264.0