Consolidated Statements of Equity (unaudited) - USD ($) $ in Millions	Total	Common Stock and Paid-in Capital	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interests
Balance, December 31, 2019 at Dec. 31, 2018	$ 337.0	$ 481.8	$ 676.7	$ (895.5)	$ 67.9	$ 6.1
Increase (Decrease) in Stockholders' Equity
Net income	24.6	0.0	24.7	0.0	0.0	(0.1)
Repurchase of common stock	(4.8)	0.0	0.0	(4.8)	0.0	0.0
Payments in consideration of employee tax obligations related to stock-based compensation	(4.3)	(4.3)	0.0	0.0	0.0	0.0
Stock-based compensation	1.9	1.9	0.0	0.0	0.0	0.0
Exercise of stock options	9.2	(2.2)	0.0	11.4	0.0	0.0
Shares issued	(0.3)	(7.4)	0.0	7.1	0.0	0.0
Dividends declared	(18.1)	0.0	(18.1)	0.0	0.0	0.0
Other comprehensive (loss) income	8.6	0.0	0.0	0.0	8.6	0.0
Balance, June 30, 2020 at Mar. 31, 2019	353.8	469.8	683.3	(881.8)	76.5	6.0
Balance, December 31, 2019 at Dec. 31, 2018	337.0	481.8	676.7	(895.5)	67.9	6.1
Increase (Decrease) in Stockholders' Equity
Net income	101.0
Other comprehensive (loss) income	(4.4)				(4.4)
Balance, June 30, 2020 at Jun. 30, 2019	387.3	470.0	741.3	(893.7)	63.5	6.2
Balance, December 31, 2019 at Mar. 31, 2019	353.8	469.8	683.3	(881.8)	76.5	6.0
Increase (Decrease) in Stockholders' Equity
Net income	76.4	0.0	76.2	0.0	0.0	0.2
Repurchase of common stock	(25.0)	0.0	0.0	(25.0)	0.0	0.0
Payments in consideration of employee tax obligations related to stock-based compensation	(0.6)	(0.6)	0.0	0.0	0.0	0.0
Stock-based compensation	3.7	3.7	0.0	0.0	0.0	0.0
Exercise of stock options	8.8	(2.4)	0.0	11.2	0.0	0.0
Shares issued	1.4	(0.5)	0.0	1.9	0.0	0.0
Dividends declared	(18.2)	0.0	(18.2)	0.0	0.0	0.0
Other comprehensive (loss) income	(13.0)	0.0	0.0	0.0	(13.0)	0.0
Balance, June 30, 2020 at Jun. 30, 2019	387.3	470.0	741.3	(893.7)	63.5	6.2
Balance, December 31, 2019 at Dec. 31, 2019	402.2	478.6	730.5	(892.2)	78.8	6.5
Increase (Decrease) in Stockholders' Equity
Net income	42.1	0.0	42.0	0.0	0.0	0.1
Repurchase of common stock	(40.4)	0.0	0.0	(40.4)	0.0	0.0
Payments in consideration of employee tax obligations related to stock-based compensation	(4.1)	(4.1)	0.0	0.0	0.0	0.0
Stock-based compensation	2.9	2.9	0.0	0.0	0.0	0.0
Shares issued	0.0	(10.3)	0.0	10.3	0.0	0.0
Dividends declared	(20.2)	0.0	(20.2)	0.0	0.0	0.0
Other comprehensive (loss) income	1.4	0.0	0.0	0.0	1.4	0.0
Balance, June 30, 2020 at Mar. 31, 2020	383.9	467.1	752.3	(922.3)	80.2	6.6
Balance, December 31, 2019 at Dec. 31, 2019	402.2	478.6	730.5	(892.2)	78.8	6.5
Increase (Decrease) in Stockholders' Equity
Net income	32.5
Other comprehensive (loss) income	(7.0)				(7.0)
Balance, June 30, 2020 at Jun. 30, 2020	349.6	469.3	725.0	(920.8)	71.8	4.3
Balance, December 31, 2019 at Mar. 31, 2020	383.9	467.1	752.3	(922.3)	80.2	6.6
Increase (Decrease) in Stockholders' Equity
Net income	(9.6)	0.0	(7.3)	0.0	0.0	(2.3)
Stock-based compensation	2.9	2.9	0.0	0.0	0.0	0.0
Shares issued	0.8	(0.7)	0.0	1.5	0.0	0.0
Dividends declared	(20.0)	0.0	(20.0)	0.0	0.0	0.0
Other comprehensive (loss) income	(8.4)	0.0	0.0	0.0	(8.4)	0.0
Balance, June 30, 2020 at Jun. 30, 2020	$ 349.6	$ 469.3	$ 725.0	$ (920.8)	$ 71.8	$ 4.3