Equity (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Sep. 30, 2017	Oct. 26, 2017
Securities Repurchase Program
Repurchase of common stock				$ 18.5
Common Stock
Securities Repurchase Program
Repurchased shares				435,710
Common Stock | Acquired Employee Equity Awards
Securities Repurchase Program
Repurchased shares		133,710
Repurchase of common stock		$ 5.8
Repurchased shares, average price (in dollars per share)		$ 43.28
Common Stock | Share Repurchase Program
Securities Repurchase Program
Repurchased shares	252,000		50,000
Repurchase of common stock	$ 10.0		$ 2.7
Repurchased shares, average price (in dollars per share)	$ 39.75		$ 53.03
Remaining amount authorized to be repurchased	$ 19.4			$ 19.4
Amount authorized to be repurchased					$ 200.0