Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Allowance for doubtful accounts receivable, current	$ 2.4	$ 1.6
Accumulated depreciation, properties and equipment	123.3	116.0
Accumulated depreciation, rental equipment	42.1	30.0
Accumulated amortization, intangible assets	$ 19.7	$ 13.4
Common stock, par value (usd per share)	$ 1	$ 1
Common stock, shares authorized (shares)	90,000,000	90,000,000
Common stock, shares issued (shares)	66,900,000	66,400,000
Treasury stock, shares (shares)	6,400,000	6,200,000