Long-Term Debt And Notes Payable (Components Of Debt) (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Debt Instrument [Line Items]
6.55% notes due 2036	$ 199,220	$ 399,092
Short-term borrowings	124,672	1,123
5.50% Notes Due 2013
Debt Instrument [Line Items]
6.55% notes due 2036	0	199,898
6.55% Notes Due 2036
Debt Instrument [Line Items]
6.55% notes due 2036	$ 199,220	$ 199,194