Stockholders' Equity (At-the-Market) (Details) - At The Market - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2021	Aug. 16, 2019
Class of Stock [Line Items]
At-the-market, maximum potential proceeds		$ 400.0
Sales commission of gross sales price		2.00%
Number of shares issued (in shares)	0
Value remaining outstanding for future offerings	$ 390.0