Earnings Per Share (Schedule Of Convertible Debt Information) (Detail) (Convertible Debt [Member], USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013		Mar. 31, 2012
New 4.0% Notes [Member]
Earnings Per Share [Line Items]
Principal amount	$ 105,322	[1]	$ 105,322	[1]
Conversion price per share	$ 15.76		$ 15.76
Number of conversion shares, principal amount	6,683		6,683
Excess over principal amount	86,316		14,512
Weighted average equivalent premium shares	3,010		809
New 4.25% Notes [Member]
Earnings Per Share [Line Items]
Principal amount	97,000	[1]	97,000	[1]
Conversion price per share	$ 15.48		$ 15.48
Number of conversion shares, principal amount	6,268		6,268
Excess over principal amount	$ 82,735		$ 15,390
Weighted average equivalent premium shares	2,885		858
Weighted Average [Member] | New 4.0% Notes [Member]
Earnings Per Share [Line Items]
Weighted average actual per share price	$ 28.68		$ 17.93
Weighted Average [Member] | New 4.25% Notes [Member]
Earnings Per Share [Line Items]
Weighted average actual per share price	$ 28.68		$ 17.93

[1] Dilutive shares associated with the New Convertible Notes are attributable to the premium over the respective conversion prices.