Earnings Per Share (Computation Of Basic And Diluted Earnings Per Share) (Detail) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Earnings Per Share [Line Items]
Less: Noncontrolling interest in subsidiaries' earnings	$ 0.3	$ 0.2
Net income attributable to common shareholders	51.1	48.7
Net income attributable to common shareholders	$ 51.3	$ 48.9
Average basic shares outstanding	58,100,000	58,500,000
Effect of dilutive stock options	808,000	998,000
Average diluted shares outstanding	58,900,000	59,500,000
Earnings per share - basic:
Net income attributable to common shareholders	$ 0.88	$ 0.83
Earnings per share - diluted:
Net income attributable to common shareholders	$ 0.87	$ 0.82