Consolidated Statement of Shareholders' Equity - USD ($) $ in Millions		Common Stock	Additional Paid-In Capital	Deferred Compensation Equity	Accumulated Other Comprehensive Income (loss).	Retained Earnings	Shares in Treasury	Total
Balance at the beginning of the period at Dec. 31, 2013		$ 78.7	$ 201.1	$ 3.0	$ (31.5)	$ 1,944.3	$ (209.5)	$ 1,986.1
Balance (in shares) at Dec. 31, 2013		63,658,777					14,761,481
Increase (Decrease) in Shareholders' Equity
Net income						251.3		251.3
Other comprehensive loss, net of tax					(30.3)			(30.3)
Cash dividends - $0.94, $1.10 and $1.30 per share for the years ended 2014, 2015 and 2016, respectively						(61.2)		(61.2)
Issuance and deferrals, net for stock based compensation (1)	[1]		46.7	3.0			$ 9.4	59.1
Issuance and deferrals, net for stock based compensation (in shares)	[1]	1,032,282					(1,038,280)
Balance at the end of the period at Dec. 31, 2014		$ 78.7	247.8	6.0	(61.8)	2,134.4	$ (200.1)	2,205.0
Balance (in shares) at Dec. 31, 2014		64,691,059					13,723,201
Increase (Decrease) in Shareholders' Equity
Net income						319.7		319.7
Other comprehensive loss, net of tax					(25.3)			(25.3)
Cash dividends - $0.94, $1.10 and $1.30 per share for the years ended 2014, 2015 and 2016, respectively						(72.3)		(72.3)
Repurchases of common stock							$ (137.2)	(137.2)
Repurchases of common stock (in Shares)		(1,496,411)					1,496,411
Issuance and deferrals, net for stock based compensation (1)	[1]		45.6	2.0			$ 9.9	57.5
Issuance and deferrals, net for stock based compensation (in shares)	[1]	856,952					(836,371)
Balance at the end of the period at Dec. 31, 2015		$ 78.7	293.4	8.0	(87.1)	2,381.8	$ (327.4)	$ 2,347.4
Balance (in shares) at Dec. 31, 2015		64,051,600					14,383,241	64,051,600
Increase (Decrease) in Shareholders' Equity
Net income						250.1		$ 250.1
Other comprehensive loss, net of tax					(35.1)			(35.1)
Cash dividends - $0.94, $1.10 and $1.30 per share for the years ended 2014, 2015 and 2016, respectively						(84.5)		(84.5)
Repurchases of common stock							$ (75.7)	(75.7)
Repurchases of common stock (in Shares)		(782,057)					782,057
Issuance and deferrals, net for stock based compensation (1)	[1]		41.9	2.3			$ 20.5	64.7
Issuance and deferrals, net for stock based compensation (in shares)	[1]	987,639					(986,497)
Balance at the end of the period at Dec. 31, 2016		$ 78.7	$ 335.3	$ 10.3	$ (122.2)	$ 2,547.4	$ (382.6)	$ 2,466.9
Balance (in shares) at Dec. 31, 2016		64,257,182					14,178,801	64,257,182

[1] Issuances and deferrals, net for stock based compensation reflects share activity related to option exercises, net of tax, restricted and performance shares vested and net issuances and deferrals associated with deferred compensation equity.