Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Millions	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Treasury Stock	Cumulative adjustment	Cumulative adjustment Retained Earnings
BALANCE (in shares) at Dec. 31, 2018		25,494,328
BALANCE at Dec. 31, 2018	$ 1,095.7	$ 0.3	$ 292.8	$ 1,394.8	$ (137.8)	$ (454.4)	$ (6.1)	$ (6.1)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	125.9
Other comprehensive income (loss), net of taxes	(31.7)				(31.7)
Net issuance of treasury shares to stock compensation plans (in shares)		9,803
Net issuance of treasury shares to stock compensation plans	2.9		(15.3)			18.1
Stock-based compensation	14.5		14.5
Dividends declared	(14.8)			(14.8)
BALANCE (in shares) at Sep. 30, 2019		25,504,131
BALANCE at Sep. 30, 2019	1,186.3	$ 0.3	292.0	1,499.8	(169.5)	(436.2)
BALANCE (in shares) at Dec. 31, 2018		25,494,328
BALANCE at Dec. 31, 2018	1,095.7	$ 0.3	292.8	1,394.8	(137.8)	(454.4)	$ (6.1)	$ (6.1)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)				125.9
BALANCE (in shares) at Dec. 31, 2019		25,486,711
BALANCE at Dec. 31, 2019	1,255.7	$ 0.3	295.3	1,542.4	(147.0)	(435.3)
BALANCE (in shares) at Jun. 30, 2019		25,510,280
BALANCE at Jun. 30, 2019	1,164.1	$ 0.3	288.2	1,467.0	(152.5)	(438.8)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	38.0			186.4
Other comprehensive income (loss), net of taxes	(17.0)				(17.0)
Net issuance of treasury shares to stock compensation plans (in shares)		(6,149)
Net issuance of treasury shares to stock compensation plans	1.9		(0.7)			2.6
Stock-based compensation	4.5		4.5
Dividends declared	(5.2)			(5.2)
BALANCE (in shares) at Sep. 30, 2019		25,504,131
BALANCE at Sep. 30, 2019	1,186.3	$ 0.3	292.0	1,499.8	(169.5)	(436.2)
BALANCE (in shares) at Dec. 31, 2019		25,486,711
BALANCE at Dec. 31, 2019	1,255.7	$ 0.3	295.3	1,542.4	(147.0)	(435.3)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	186.4
Other comprehensive income (loss), net of taxes	(59.3)				(59.3)
Purchases of treasury stock	(48.9)					(48.9)
Net issuance of treasury shares to stock compensation plans (in shares)		(46,964)
Net issuance of treasury shares to stock compensation plans	1.6		(18.4)			20.0
Stock-based compensation	27.0		27.0
Dividends declared	(5.5)			(5.5)
BALANCE (in shares) at Sep. 30, 2020		25,439,746
BALANCE at Sep. 30, 2020	1,356.9	$ 0.3	304.0	1,723.3	(206.3)	(464.3)
BALANCE (in shares) at Jun. 30, 2020		25,439,581
BALANCE at Jun. 30, 2020	1,215.9	$ 0.3	300.0	1,596.9	(213.3)	(467.9)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	126.4
Other comprehensive income (loss), net of taxes	7.0				7.0
Net issuance of treasury shares to stock compensation plans (in shares)		165
Net issuance of treasury shares to stock compensation plans	2.2		(1.4)			3.6
Stock-based compensation	5.3		5.3
BALANCE (in shares) at Sep. 30, 2020		25,439,746
BALANCE at Sep. 30, 2020	$ 1,356.9	$ 0.3	$ 304.0	$ 1,723.3	$ (206.3)	$ (464.3)