Consolidated Statements of Stockholders' Equity - USD ($) $ in Millions	Total	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Loss
Beginning balance at Dec. 31, 2018	$ 1,464.2	$ 1.3	$ 1,131.9	$ 392.3	$ (61.3)
Beginning balance (in shares) at Dec. 31, 2018		132,900,000
Increase (Decrease) in Stockholders' Equity
Cumulative effect adjustment for adoption of new accounting standard, net of tax	1.1			1.1
Net income	77.8			77.8
Other comprehensive income (loss)	8.1				8.1
Issuance of common stock under stock plans	0.7		0.7
Issuance of common stock under stock plans (in shares)		600,000
Surrender of RSUs for taxes	(10.2)		(10.2)
Surrender of RSUs for taxes (in shares)		(200,000)
Stock-based compensation expense	7.4		7.4
Dividends earned under stock plan	0.0		1.7	(1.7)
Cash dividends declared to stockholders	(46.6)			(46.6)
Ending balance at Mar. 31, 2019	1,502.5	$ 1.3	1,131.5	422.9	(53.2)
Ending balance (in shares) at Mar. 31, 2019		133,300,000
Beginning balance at Dec. 31, 2019	$ 1,650.2	$ 1.3	1,028.9	651.0	(31.0)
Beginning balance (in shares) at Dec. 31, 2019	128,833,452	128,800,000
Increase (Decrease) in Stockholders' Equity
Cumulative effect adjustment for adoption of new accounting standard, net of tax	$ (3.8)			(3.8)
Net income	2.8			2.8
Other comprehensive income (loss)	(54.9)				(54.9)
Issuance of common stock under stock plans	0.4		0.4
Issuance of common stock under stock plans (in shares)		500,000
Surrender of RSUs for taxes	(3.4)		(3.4)
Surrender of RSUs for taxes (in shares)		(100,000)
Stock-based compensation expense	5.0		5.0
Dividends earned under stock plan	0.0		0.7	(0.7)
Cash dividends declared to stockholders	(24.5)			(24.5)
Ending balance at Mar. 31, 2020	$ 1,571.8	$ 1.3	$ 1,031.6	$ 624.8	$ (85.9)
Ending balance (in shares) at Mar. 31, 2020	129,161,707	129,200,000