Stockholders' Equity - Dividends (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Accumulated Other Comprehensive Loss
Dividends declared per common share (in dollars per share)	$ 0.90	$ 0.85
Aggregated dividend paid	$ 46.3
Dividend payable date declared	Feb. 26, 2019
Common stock dividend payable date	Apr. 15, 2019
Dividend payable date of record	Mar. 29, 2019