Stock Repurchases (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014		Dec. 31, 2013	Mar. 07, 2013
Equity, Class of Treasury Stock [Line Items]
Increase in number of shares authorized for repurchase						1,000,000
Number of shares authorized for repurchase		860,450
Common stock repurchased, shares		470,071	2,686,744		1,216,015
Common stock repurchased, value		$ 86.5	$ 343.7		$ 135.2
Open Market [Member]
Equity, Class of Treasury Stock [Line Items]
Common stock repurchased, shares		464,006	0		1,209,756
Common stock repurchased, value		$ 85.4	$ 0.0		$ 134.5
Tender Offer [Member]
Equity, Class of Treasury Stock [Line Items]
Common stock repurchased, shares		0	2,548,868		0
Common stock repurchased, value		$ 0.0	$ 325.3	[1]	$ 0.0
Tender offer, offering costs		$ 0.3
Other [Member]
Equity, Class of Treasury Stock [Line Items]
Common stock repurchased, shares	[2]	6,065	137,876		6,259
Common stock repurchased, value		$ 1.1	$ 18.4		$ 0.7

[1] Tender Offer Cost amounts include offering costs of $0.3 million for 2014.

[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.