Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Statement Of Financial Position [Abstract]
Property, plant and equipment, accumulated depreciation and amortization	$ 432.1	$ 412.9
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	62,055,122	61,553,724
Common stock, shares outstanding	48,661,946	48,808,239
Treasury stock, shares	13,393,176	12,745,485