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				6 Months Ended
	Jun. 30, 2013		Jun. 30, 2012		Jun. 30, 2013		Jun. 30, 2012		Dec. 31, 2012
New 4.0% Notes [Member]
Earnings Per Share [Line Items]
Principal amount	$ 105,322	[1]	$ 105,322	[1]	$ 105,322	[1]	$ 105,322	[1]	$ 105,300
Conversion price per share	$ 15.76		$ 15.76		$ 15.76		$ 15.76
Number of conversion shares, principal amount	6,683		6,683		6,683		6,683
Excess over principal amount	96,021		4,261		91,325		9,345
Weighted average equivalent premium shares	3,187		260		3,104		545
New 4.25% Notes [Member]
Earnings Per Share [Line Items]
Principal amount	97,000	[1]	97,000	[1]	97,000	[1]	97,000	[1]	97,000
Conversion price per share	$ 15.48		$ 15.48		$ 15.48		$ 15.48
Number of conversion shares, principal amount	6,268		6,268		6,268		6,268
Excess over principal amount	$ 91,837		$ 5,777		$ 87,433		$ 10,545
Weighted average equivalent premium shares	3,048		352		2,971		615
Weighted Average [Member] | New 4.0% Notes [Member]
Earnings Per Share [Line Items]
Weighted average actual per share price	$ 30.13		$ 16.40		$ 29.43		$ 17.16
Weighted Average [Member] | New 4.25% Notes [Member]
Earnings Per Share [Line Items]
Weighted average actual per share price	$ 30.13		$ 16.40		$ 29.43		$ 17.16

[1] Dilutive shares associated with the New Convertible Notes are attributable to the weighted average premium value, in shares, of the conversion shares underlying the New Convertible Notes in excess of the respective principal amounts thereof.