Stock Repurchases (Details) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Equity, Class of Treasury Stock [Line Items]
Increase in number of shares authorized for repurchase	1,000,000
Number of shares authorized for repurchase	324,456
Common stock repurchased, shares	1,216,015		1,740,372		1,979,444
Common stock repurchased, value	$ 135.2	[1]	$ 152.5	[1]	$ 130.8	[1]
Tender offer, offering costs			0.3		0.2
Open Market [Member]
Equity, Class of Treasury Stock [Line Items]
Common stock repurchased, shares	1,209,756		727,319		55,133
Common stock repurchased, value	134.5	[1]	66.5	[1]	4.2	[1]
Tender Offer [Member]
Equity, Class of Treasury Stock [Line Items]
Common stock repurchased, shares			1,000,000		1,904,761
Common stock repurchased, value			84.8	[1]	125.2	[1]
Other [Member]
Equity, Class of Treasury Stock [Line Items]
Common stock repurchased, shares	6,259	[2]	13,053	[2]	19,550	[2]
Common stock repurchased, value	$ 0.7	[1],[2]	$ 1.2	[1],[2]	$ 1.4	[1],[2]

[1] Tender Offer Cost amounts include offering costs of $0.3 million and $0.2 million for 2012 and 2011, respectively.

[2] Represents shares of common stock released to us by team members as payment of tax withholdings due to us upon the vesting of restricted stock and restricted stock units.