Earnings Per Share and Shareholders' Equity Transactions (Information Regarding Basic and Diluted Earnings Per Share) (Details) - $ / shares shares in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Basic shares used in the calculation of earnings per share	37.7	40.0	42.4
Diluted shares used in the calculation of earnings per share	38.1	40.6	43.0
Per share effect of dilutive securities on income from continuing operations	$ (0.11)	$ (0.16)	$ (0.07)
Per share effect of dilutive securities on net income	$ (0.10)	$ (0.16)	$ (0.12)
Employee Stock Option [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Dilutive effect of securities	0.2	0.3	0.3
Non-Vested Stock Grants [Member]
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Dilutive effect of securities	0.2	0.3	0.3