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		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Earnings Per Share [Abstract]
Net income attributable to common shareholders	$ 59,697	$ 54,874	$ 108,381	$ 112,665
Average basic shares outstanding	58,883	57,908	58,682	57,684
Effect of dilutive stock options	960	920	982	910
Average diluted shares outstanding	59,843	58,828	59,664	58,594
Earnings per share - basic:
Net income attributable to common shareholders	$ 1.01	$ 0.95	$ 1.85	$ 1.95
Earnings per share - diluted:
Net income attributable to common shareholders	$ 1.00	$ 0.93	$ 1.82	$ 1.92