Summary Of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2012

Summary Of Significant Accounting Policies [Abstract]

Schedule Of Long-Term Investments Measured At Fair Value Using Significant Unobservable Inputs (Level 3 Inputs)

(in thousands)	2012			2011
Balance as of January 1	$	24,673		$	35,297
Net unrealized gains included in other comprehensive income		1,476			526
Sales of investments at par value		(15,825	)		(11,150	)
Balance as of December 31	$	10,324		$	24,673
Unrealized losses still held	$	1,851		$	3,327

Schedule Of Calculation Of Basic And Diluted Earnings Per Share

	Year Ended December 31,
(in thousands, except per share data)	2012		2011		2010
Net income	$	56,607	$	51,959	$	79,758
Denominator for basic earnings per share – weighted- average number of common shares outstanding during the period		56,320		59,284		62,141
Incremental common shares attributable to exercise of outstanding dilutive options		150		270		455
Incremental common shares attributable to outstanding restricted shares, restricted stock units and phantom stock		164		219		96
Denominator for diluted earnings per share		56,634		59,773		62,692
Basic earnings per share	$	1.01	$	0.88	$	1.28
Diluted earnings per share	$	1.00	$	0.87	$	1.27

Summary Of Weighted-Average Assumptions Used To Value Option Grants

	Year Ended December 31,
	2012			2011			2010
Stock Options
Expected term of options		6.3 years			6.2 years			7.0 years
Expected volatility		42	%		41	%		40	%
Risk-free interest rate		1.305	%		2.674	%		2.94	%
Dividend yield		zero			zero			zero