CONDENSED CONSOLIDATED STATEMENT OF EQUITY (UNAUDITED) (USD $) In Millions, unless otherwise specified	Total	Common Stock [Member]	Capital in Excess of Par Value [Member]	Treasury Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive (Loss) Income [Member]
Balance at Dec. 31, 2011	$ 654.9	$ 8.6	$ 76.3	$ (23.0)	$ 664.5	$ (71.5)
Balance (in shares) at Dec. 31, 2011		34.3		(0.6)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	59.6				59.6
Stock-based compensation	8.1		8.1
Shares issued under stock plans	6.9		(8.3)	15.2
Shares issued under stock plans (in shares)				0.4
Shares repurchased for employee tax withholdings	(2.2)			(2.2)
Excess tax benefit from employee stock plans	2.3		2.3
Dividends declared	(12.2)				(12.2)
Other comprehensive loss, net of tax	(0.3)					(0.3)
Balance at Sep. 30, 2012	$ 717.1	$ 8.6	$ 78.4	$ (10.0)	$ 711.9	$ (71.8)
Balance (in shares) at Sep. 30, 2012		34.3		(0.2)