Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Millions	Total	Common Stock	Capital in Excess of Par Value	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Loss
Beginning Balance at Dec. 31, 2014	$ 371.6	$ 64.2	$ 187.0	$ 227.0	$ (27.1)	$ (79.5)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	52.0			52.0
Total other comprehensive (loss) income	(5.3)					(5.3)
Cash dividends declared	11.3			11.3
Stock-based payments:
Stock-based compensation	4.3		4.3
Stock option exercises and other	0.7	0.1	1.1		(0.5)
Performance share unit transactions	(2.7)	0.5	(0.5)		(2.7)
Excess tax benefit from stock-based compensation	0.5		0.5
Stock repurchase program	10.6				10.6
Ending Balance at Sep. 30, 2015	399.2	64.8	192.4	267.7	(40.9)	(84.8)
Beginning Balance at Jun. 30, 2015						(84.6)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	18.8
Total other comprehensive (loss) income	(0.2)					(0.2)
Ending Balance at Sep. 30, 2015	399.2	64.8	192.4	267.7	(40.9)	(84.8)
Beginning Balance at Dec. 31, 2015	405.6	64.8	195.6	274.9	(40.9)	(88.8)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	31.2			31.2
Total other comprehensive (loss) income	10.1					10.1
Cash dividends declared	12.8			12.8
Stock-based payments:
Stock-based compensation	2.9		2.9
Stock option exercises and other	0.7	0.2	0.7		(0.2)
Performance share unit transactions	(2.4)	0.4	(0.4)		(2.4)
Stock repurchase program	33.8				33.8
Ending Balance at Sep. 30, 2016	401.5	65.4	198.8	293.3	(77.3)	(78.7)
Beginning Balance at Jun. 30, 2016						(79.1)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	8.5
Total other comprehensive (loss) income	0.4					0.4
Ending Balance at Sep. 30, 2016	$ 401.5	$ 65.4	$ 198.8	$ 293.3	$ (77.3)	$ (78.7)