Equity (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Mar. 31, 2017	Jun. 30, 2017
Securities Repurchase Program
Repurchase of common stock			$ 8.5
Common Stock
Securities Repurchase Program
Repurchased shares			183,710
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		50,000
Repurchase of common stock		$ 2.7
Repurchased shares, average price (in dollars per share)		$ 53.03
Amount authorized to be repurchased	$ 29.5		$ 29.5