Stock Based Compensation (Details) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended						3 Months Ended		12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2012 Treasury Stock [Member]	Dec. 31, 2012 Performance Shares [Member]	Dec. 31, 2012 Performance Units Related to Earnings Per Share [Member]	Dec. 31, 2012 Total Shareholder Return [Member]	Dec. 31, 2012 Restricted Stock [Member]	Dec. 31, 2012 Performance Units Related to Earnings Per Share [Member]		Dec. 31, 2011 Performance Units Related to Earnings Per Share [Member]	Dec. 31, 2010 Performance Units Related to Earnings Per Share [Member]	Dec. 31, 2012 Total Shareholder Return [Member]		Dec. 31, 2011 Total Shareholder Return [Member]	Dec. 31, 2010 Total Shareholder Return [Member]	Dec. 31, 2012 Performance Shares [Member]	Dec. 31, 2011 Performance Shares [Member]	Dec. 31, 2010 Performance Shares [Member]	Dec. 31, 2012 Restricted Stock [Member]		Dec. 31, 2011 Restricted Stock [Member]	Dec. 31, 2010 Restricted Stock [Member]	Dec. 31, 2012 Stock Compensation Plan [Member]	Dec. 31, 2011 Stock Compensation Plan [Member]	Dec. 31, 2010 Stock Compensation Plan [Member]	Dec. 31, 2012 Performance Units Related to Earnings Per Share [Member] Performance Shares [Member]	Dec. 31, 2011 Performance Units Related to Earnings Per Share [Member] Performance Shares [Member]	Dec. 31, 2010 Performance Units Related to Earnings Per Share [Member] Performance Shares [Member]	Dec. 31, 2012 Total Shareholder Return [Member] Performance Shares [Member]	Dec. 31, 2011 Total Shareholder Return [Member] Performance Shares [Member]	Dec. 31, 2010 Total Shareholder Return [Member] Performance Shares [Member]	Dec. 31, 2012 Common Stock [Member]	Dec. 31, 2011 Common Stock [Member]	Dec. 31, 2010 Common Stock [Member]	Dec. 31, 2012 Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares Authorized	2,750,000
Compensation Expense																				$ 12.2	$ 13.7	$ 9.3	$ 0.6		$ 1.0	$ 0.9	$ 12.8	$ 14.7	$ 10.2	$ 4.2	$ 5.5	$ 2.5	$ 8.0	$ 8.2	$ 6.8
Tax Benefit from Compensation Expense	4.9		5.7		3.9
Shares Issued in Period																																				424,555	311,623	255,389
Shares Paid for Tax Withholding																																							5,911
Treasury Stock, Shares, Acquired							60,000
Treasury Stock Acquired, Average Cost Per Share							$ 55.41
Equity Instruments Other than Options, Grants in Period												40,797	[1]	71,238	71,585	169,339	[1]	213,721	214,750				5,412	[1]	17,902	26,653
Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value												$ 47.63		$ 41.61	$ 32.44	$ 51.82		$ 46.09	$ 39.43				$ 53.44		$ 48.82	$ 40.78
Expected Dividend Rate																3.00%		3.20%	3.90%
Expected Volatility Rate																22.00%		33.00%	34.00%
Risk Free Interest Rate																0.38%		1.40%	1.42%
Expected Term																2 years 10 months 13 days		2 years 10 months 13 days	2 years 10 months 13 days
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]
Equity Instruments Other Than Options Outstanding Number, Beginning Balance												235,376				706,124							37,244
Equity Instruments Other than Options, Converted in Period												(97,099)	[2]			(291,294)	[2]
Equity Instruments Other than Options, Vested in Period												(62,880)				(188,633)							(15,847)
Equity Instruments Other than Options, Forfeited in Period												(15,155)				(49,605)							(2,256)
Equity Instruments Other Than Options Outstanding Number, Ending Balance												163,919		235,376		534,564		706,124					24,553		37,244
Awards Other than Options, Fully Vested												62,880				188,633
Equity Instruments Other than Options, Converted, Aggregrate Intrinsic Value												10.2	[2]			30.6	[2]
Equity Instruments Other than Options, Vested in Period, Aggregate Intrinsic Value																							0.9
Equity Instruments Other than Options, Outstanding, Aggregrate Intrinsic Value												13.8				46.3							1.4
Equity Instruments Other than Options, Fully Vested, Aggregrate Intrinsic Value												7.1				21.2
Minimum payout range	0.00%
Maximum payout range	200.00%
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Equity Instruments Other than Options, Nonvested, Number, Beginning Balance												138,277				414,830							37,244
Equity Instruments Other than Options, Grants in Period												40,797	[1]	71,238	71,585	169,339	[1]	213,721	214,750				5,412	[1]	17,902	26,653
Equity Instruments Other than Options, Vested in Period												(62,880)				(188,633)							(15,847)
Equity Instruments Other than Options, Forfeited in Period												(15,155)				(49,605)							(2,256)
Equity Instruments Other than Options, Nonvested, Number, Ending Balance												101,039		138,277		345,931		414,830					24,553		37,244
Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value												$ 44.00		$ 37.01		$ 48.79		$ 42.75					$ 47.21		$ 44.24
Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value												$ 32.44				$ 39.43							$ 42.78
Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value												$ 38.02				$ 44.24							$ 44.22
Awards Other than Options, Vested and Expected to Vest, Outstanding												94,557				323,303							24,553
Fair Value of Vested Performance Units and Restricted Stock												4.1		3.9	1.9	7.4		7.4	5.4				0.7		1.0	0.6
Total Compensation Cost Not yet Recognized	12.1							11.6	3.9	7.7	0.5
Total Compensation Cost Not yet Recognized, Period for Recognition									1 year 1 month 21 days	1 year 7 months 21 days	1 year 11 months 16 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options, Outstanding, Beginning Balance	55,800
Options, Exercises in Period	(36,200)
Options, Outstanding, Ending Balance	19,600		55,800
Options, Outstanding, Weighted Average Exercise Price	$ 22.80		$ 23.19
Options, Exercises in Period, Weighted Average Exercise Price	$ 23.41
Options, Exercises in Period, Total Intrinsic Value	2.0	[3]	2.2	[3]	2.5	[3]
Options, Outstanding, Intrinsic Value	0.6
Options, Outstanding, Weighted Average Remaining Contractual Term	11 months 12 days
Options, Exercisable	19,600
Options, Exercisable, Weighted Average Exercise Price	$ 22.80
Options, Exercisable, Intrinsic Value	0.6
Options, Exercisable, Weighted Average Remaining Contractual Term	11 months 12 days
Cash Received from Exercise of Stock Options	0.8		1.3		3.2
Tax Benefit Realized from Exercise of Stock Options	$ 0	[4]	$ 0	[4]	$ 1.0	[4]

[1] For performance units, this represents the target number of performance units granted. Actual number of performance units earned, if any, is dependent upon performance and may range from 0 percent to 200 percent of the target.

[2] These amounts represent performance units that vested at December 31, 2011 which were settled in February 2012.

[3] The difference between the market value on the date of exercise and the option exercise price.

[4] The Company did not realize an income tax benefit for the tax deductions from the exercised stock options in 2012 and 2011 due to the Company being in a tax net operating loss position in 2012 and 2011.