Stockholders' Equity Shares Repurchases (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2020	Dec. 01, 2018
Equity, Class of Treasury Stock [Line Items]
Stock Repurchased During Period, Shares	902,340
Treasury Stock Acquired, Average Cost Per Share	$ 69.46
Treasury Stock, Value, Acquired, Par Value Method	$ 62.7
2018 Stock Repurchase Program [Member] [Member]
Equity, Class of Treasury Stock [Line Items]
Stock Repurchase Program, Authorized Amount	$ 37.3	$ 100.0