Consolidated Statements of Stockholders' Equity - USD ($) shares in Millions, $ in Millions	Total	Common stock	Additional paid-in capital	Treasury stock	Retained earnings	Accumulated other comprehensive loss
Beginning balance at Dec. 31, 2017	$ 555.2	$ 0.5	$ 276.8	$ (75.1)	$ 355.1	$ (2.1)
Beginning balance (in shares) at Dec. 31, 2017		52.4		6.2
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued, net of shares withheld for employee taxes			(1.7)
Stock-based compensation expense			8.2
Repurchase of common stock				$ (15.5)
Net income	45.5				45.5
Dividends declared					(19.0)
Other comprehensive income (loss)	(5.7)					(5.7)
Common stock issued, net of shares withheld for employee taxes (in shares)		0.1
Repurchase of common stock (in shares)				(0.6)
Ending balance at Dec. 31, 2018	$ 567.0	$ 0.5	283.3	$ (90.6)	381.6	(7.8)
Ending balance (in shares) at Dec. 31, 2018	45.7	52.5		6.8
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared per share (in dollars per share)	$ 0.41
Common stock issued, net of shares withheld for employee taxes			(2.3)
Stock-based compensation expense			9.6
Repurchase of common stock				$ (22.0)
Net income	$ 57.7				57.7
Dividends declared					(20.8)
Other comprehensive income (loss)	2.7					2.7
Common stock issued, net of shares withheld for employee taxes (in shares)		0.2
Repurchase of common stock (in shares)				(0.8)
Ending balance at Dec. 31, 2019	$ 591.9	$ 0.5	290.6	$ (112.6)	418.5	(5.1)
Ending balance (in shares) at Dec. 31, 2019	45.1	52.7		7.6
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared per share (in dollars per share)	$ 0.45
Common stock issued, net of shares withheld for employee taxes			(2.5)
Stock-based compensation expense			10.2
Repurchase of common stock				$ (10.4)
Net income	$ 63.2				63.2
Dividends declared					(22.0)
Other comprehensive income (loss)	1.5					1.5
Common stock issued, net of shares withheld for employee taxes (in shares)		0.2
Repurchase of common stock (in shares)				(0.4)
Ending balance at Dec. 31, 2020	$ 631.9		$ 298.3	$ (123.0)	$ 459.7	$ (3.6)
Ending balance (in shares) at Dec. 31, 2020	44.9	52.9		8.0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared per share (in dollars per share)	$ 0.49