Equity (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2018
Securities Repurchase Program
Repurchase of common stock			$ 55.8
Acquired Employee Equity Awards
Securities Repurchase Program
Repurchased shares	119,608
Repurchase of common stock	$ 5.8
Repurchased shares, average price (in dollars per share)	$ 48.61
Share Repurchase Program
Securities Repurchase Program
Repurchased shares		1,133,016
Repurchase of common stock		$ 50.0
Repurchased shares, average price (in dollars per share)		$ 44.13
Remaining amount authorized to be repurchased	$ 150.0		$ 150.0
Common Stock
Securities Repurchase Program
Repurchased shares			1,252,624