Earnings Per Share (Schedule Of Convertible Note Premium Share Information) (Detail) (Unsecured Debt [Member], Convertible Debt [Member], USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
2011 4.0% Notes [Member]
Premium Share Information:
Number of conversion shares, principal amount	6,683	6,683	6,683
Weighted average equivalent premium shares	3,270	1,044	1,067
2011 4.25% Notes [Member]
Premium Share Information:
Number of conversion shares, principal amount	6,268	6,268	6,268
Weighted average equivalent premium shares	3,125	1,074	1,095
Weighted Average [Member] | 2011 4.0% Notes [Member]
Premium Share Information:
Weighted average actual per share price	$ 30.86	$ 18.68	$ 18.90
Weighted average premium value	$ 100,911	$ 19,494	$ 20,968
Weighted Average [Member] | 2011 4.25% Notes [Member]
Premium Share Information:
Weighted average actual per share price	$ 30.86	$ 18.68	$ 18.88
Weighted average premium value	$ 96,423	$ 20,064	$ 21,319