Stockholders' Equity - Dividends (Details) - USD ($) $ / shares in Units, $ in Millions									12 Months Ended
	Dec. 18, 2020	Nov. 05, 2020	Sep. 18, 2020	Aug. 06, 2020	Jun. 19, 2020	May 07, 2020	Mar. 27, 2020	Feb. 24, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Equity [Abstract]
Dividends declared per share (in dollars per share)		$ 0.13		$ 0.12		$ 0.12		$ 0.12	$ 0.49	$ 0.45	$ 0.41
Cash payment amount	$ 5.7		$ 5.4		$ 5.4		$ 5.5		$ 22.3	$ 20.7	$ 18.9