CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (USD $)	Total	Common Stock	Capital in Excess of Par Value	Treasury Stock, at Cost	Accumulated Other Comprehensive Loss	Retained Earnings	Pension liability [Member]	Pension liability [Member] Accumulated Other Comprehensive Loss	Postretirement medical liability [Member]	Postretirement medical liability [Member] Accumulated Other Comprehensive Loss	Officers supplemental retirement plan [Member]	Officers supplemental retirement plan [Member] Accumulated Other Comprehensive Loss
Stockholders' Equity Attributable to Parent at Dec. 31, 2008	$ 661,900,000	$ 43,200,000	$ 915,000,000	$ (161,400,000)	$ (328,300,000)	$ 193,400,000
Common Stock, Shares, Outstanding at Dec. 31, 2008		36,275,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)	121,600,000					121,600,000
Related to Marketable Securities [Abstract]
Change in Fair Value					20,400,000
Reclassification to Earnings					(2,500,000)
Income Tax Effect					(6,700,000)
Marketable Securities, Net of Tax	11,200,000				11,200,000
Related to Employee Benefit Plans [Abstract]
Pension Liability Adjustment, Net of Tax							71,900,000	71,900,000	3,900,000	3,900,000	(200,000)	(200,000)
Related to Interest Rate Derivative Instruments [Abstract]
Change in Fair Value					2,400,000
Income Tax Effect					(900,000)
Interest Rate Derivative Instruments, Net of Tax	1,500,000				1,500,000
Total Comprehensive Income	209,900,000
Purchase of Treasury Stock (Share)	(1,324,578)	(1,325,000)
Purchase of Treasury Stock	(23,800,000)	0	0	(23,800,000)
Stock-based Compensation	11,900,000	0	11,900,000	0
Treasury Stock Issued Under Stock Plans (Share)		69,000
Treasury Stock Issued Under Stock Plans	1,500,000	0	0	1,500,000
Delisting of Treasury Shares	0	(7,900,000)	(170,100,000)	178,000,000
Stock Issued for Employee Stock Purchase Plan (Shares)		185,000
Stock Issued for Employee Stock Purchase Plan	3,100,000	200,000	2,900,000	0
Stock Issued Under Stock Plans (Shares)		387,000
Stock Issued Under Stock Plans	7,600,000	300,000	7,300,000	0
Stockholders' Equity Attributable to Parent at Dec. 31, 2009	872,100,000	35,800,000	767,000,000	(5,700,000)	(240,000,000)	315,000,000
Common Stock, Shares, Outstanding at Dec. 31, 2009		35,591,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)	251,100,000					251,100,000
Related to Marketable Securities [Abstract]
Change in Fair Value					7,200,000
Reclassification to Earnings					(8,300,000)
Income Tax Effect					400,000
Marketable Securities, Net of Tax	(700,000)				(700,000)
Related to Employee Benefit Plans [Abstract]
Pension Liability Adjustment, Net of Tax							(14,200,000)	(14,200,000)	(2,900,000)	(2,900,000)	(2,400,000)	(2,400,000)
Related to Interest Rate Derivative Instruments [Abstract]
Change in Fair Value					(11,200,000)
Income Tax Effect					4,200,000
Interest Rate Derivative Instruments, Net of Tax	(7,000,000)				(7,000,000)
Total Comprehensive Income	223,900,000
Purchase of Treasury Stock (Share)	(1,000,748)	(1,001,000)
Purchase of Treasury Stock	(45,100,000)	0	0	(45,100,000)
Stock-based Compensation	13,700,000	0	13,700,000	0
Treasury Stock Issued Under Stock Plans (Share)		167,000
Treasury Stock Issued Under Stock Plans	4,800,000	0	0	4,800,000
Stock Issued for Employee Stock Purchase Plan (Shares)		16,000
Stock Issued for Employee Stock Purchase Plan	0	0	0	0
Stock Issued Under Stock Plans (Shares)		1,151,000
Stock Issued Under Stock Plans	36,000,000	1,200,000	34,800,000	0
Stockholders' Equity Attributable to Parent at Dec. 31, 2010	1,105,400,000	37,000,000	815,500,000	(46,000,000)	(267,200,000)	566,100,000
Common Stock, Shares, Outstanding at Dec. 31, 2010		35,924,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)	244,500,000					244,500,000
Related to Marketable Securities [Abstract]
Change in Fair Value					(1,200,000)
Reclassification to Earnings					(2,500,000)
Income Tax Effect					1,400,000
Marketable Securities, Net of Tax	(2,300,000)				(2,300,000)
Related to Employee Benefit Plans [Abstract]
Pension Liability Adjustment, Net of Tax							(123,900,000)	(123,900,000)	15,300,000	15,300,000	(1,700,000)	(1,700,000)
Related to Interest Rate Derivative Instruments [Abstract]
Change in Fair Value					(20,000,000)
Income Tax Effect					9,800,000
Interest Rate Derivative Instruments, Net of Tax	(10,200,000)				(10,200,000)
Total Comprehensive Income	121,700,000
Purchase of Treasury Stock (Share)	(1,309,300)	(1,309,000)
Purchase of Treasury Stock	(79,500,000)	0	0	(79,500,000)
Stock-based Compensation	11,600,000	0	11,600,000	0
Treasury Stock Issued Under Stock Plans (Share)		4,000
Treasury Stock Issued Under Stock Plans	200,000	0	0	200,000
Stock Issued for Employee Stock Purchase Plan (Shares)		63,000
Stock Issued for Employee Stock Purchase Plan	2,800,000	100,000	2,700,000	0
Stock Issued Under Stock Plans (Shares)		793,000
Stock Issued Under Stock Plans	11,000,000	800,000	10,200,000	0
Stockholders' Equity Attributable to Parent at Dec. 31, 2011	$ 1,173,200,000	$ 37,900,000	$ 840,000,000	$ (125,300,000)	$ (390,000,000)	$ 810,600,000
Common Stock, Shares, Outstanding at Dec. 31, 2011		35,475,000