Net Income (Loss) per Common Share (Details) - shares shares in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Securities Included and Excluded from the Computation of Earnings Per Share
Weighted average shares excluded from computation of diluted earnings per share (in shares)	0.7	0.2
Employee Stock Option
Securities Included and Excluded from the Computation of Earnings Per Share
Weighted average shares excluded from computation of diluted earnings per share (in shares)	0.5	0.2
Performance Share Units And Restricted Stock Units
Securities Included and Excluded from the Computation of Earnings Per Share
Weighted average shares excluded from computation of diluted earnings per share (in shares)	0.2