Earnings Per Share (Computation Of Basic And Diluted Earnings Per Share) (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Disclosure Earnings Per Share Computation Of Basic And Diluted Earnings Per Share [Abstract]
Income from continuing operations	$ 57,483	$ 56,406	$ 170,839	$ 150,217
Less: Non-controlling interest in subsidiaries' earnings	352	182	1,043	501
Income from continuing operations attributable to common shareholders	57,131	56,224	169,796	149,716
Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	0	901	0	21,633
Net income attributable to common shareholders	57,131	57,125	169,796	171,349
Average basic shares outstanding	58,093	57,123	57,814	57,565
Effect of dilutive stock options	942	750	923	870
Average diluted shares outstanding	59,035	57,873	58,737	58,435
Earnings per share - basic:
Income from continuing operations attributable to common shareholders	$ 0.98	$ 0.99	$ 2.94	$ 2.61
Discontinued operations, net of tax	$ 0.00	$ 0.02	$ 0.00	$ 0.38
Net income attributable to common shareholders	$ 0.98	$ 1.00	$ 2.94	$ 2.98
Earnings per share - diluted:
Income from continuing operations attributable to common shareholders	$ 0.97	$ 0.97	$ 2.89	$ 2.56
Discontinued operations, net of tax	$ 0.00	$ 0.02	$ 0.00	$ 0.37
Net income attributable to common shareholders	$ 0.97	$ 0.99	$ 2.89	$ 2.93
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	$ 57,483	$ 57,307	$ 170,839	$ 171,850