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)
BALANCE (ASC 842) at Dec. 31, 2018								$ (6.1)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	87.9
Other comprehensive income (loss), net of taxes	(14.8)				(14.8)
Stock Issued During Period, Value, Employee Stock Purchase Plan			(14.6)			15.6
Net issuance of treasury shares to employee stock compensation plans (in shares)		15,953
Net issuance of treasury shares to stock compensation plans	1.0
Stock-based compensation	10.0		10.0
Dividends declared	(9.7)			(9.7)
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)
BALANCE (in shares) at Mar. 31, 2019		25,522,383
BALANCE at Mar. 31, 2019	1,127.7	$ 0.3	287.1	1,422.6	(138.7)	(443.5)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	49.2
Other comprehensive income (loss), net of taxes	(13.8)				(13.8)
Net issuance of treasury shares to employee stock compensation plans (in shares)		(12,102)
Net issuance of treasury shares to stock compensation plans	1.8		(2.8)			4.7
Stock-based compensation	3.9		3.9
Dividends declared	(4.8)			(4.8)
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)
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)	60.0
Other comprehensive income (loss), net of taxes	(66.4)				(66.4)
Purchases of treasury stock	(48.9)					(48.9)
Net issuance of treasury shares to employee stock compensation plans (in shares)		(47,129)
Net issuance of treasury shares to stock compensation plans	(0.7)		(17.0)			16.3
Stock-based compensation	21.7		21.7
Dividends declared	(5.5)			(5.5)
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)
BALANCE (in shares) at Mar. 31, 2020		25,448,275
BALANCE at Mar. 31, 2020	1,174.6	$ 0.3	287.8	1,566.7	(206.0)	(474.1)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	30.2
Other comprehensive income (loss), net of taxes	(7.3)				(7.3)
Net issuance of treasury shares to employee stock compensation plans (in shares)		(8,693)
Net issuance of treasury shares to stock compensation plans	1.8		(4.4)			6.2
Stock-based compensation	16.6		16.6
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)