Commitments and Contingencies (Details) - October 2015 Share Repurchase Program - USD ($) $ / shares in Units, $ in Millions	2 Months Ended	4 Months Ended	12 Months Ended	14 Months Ended
	Dec. 31, 2015	Apr. 21, 2017	Dec. 31, 2016	Dec. 31, 2016	Oct. 26, 2015
Stock Repurchases
Amount authorized under stock repurchase plan					$ 200.0
Share repurchases made in open market (in shares)	345,044	0	1,828,183	2,173,227
Average Price Paid per Share (in dollars per share)	$ 53.46		$ 58.40
Aggregate Cost	$ 18.4		$ 106.8	$ 125.2