Earnings Per Share (Tables)

12 Months Ended

Dec. 31, 2011

Earnings Per Share [Abstract]

Summary Of Earnings Per Share, Basic And Diluted

	2011		2010			2009
Numerator for basic earnings per share:
Net income	$	147,335	$	107,896		$	89,052
Convertible preferred stock accrued dividends		—		(1,488	)		(15,789	)
Earnings attributable to common shareholders for basic earnings per share	$	147,335	$	106,408		$	73,263
Numerator for diluted earnings per share:
Income attributable to common shareholders for basic earnings per share	$	147,335	$	106,408		$	73,263
Effect of convertible preferred stock		—		1,488			15,789
Net earnings for diluted earnings per share	$	147,335	$	107,896		$	89,052
Denominator for basic and diluted earnings per share:
Weighted-average shares outstanding		79,477		33,704			32,522
Share-based payment awards classified as participating securities		1,133		1,730			1,280
Denominator for basic earnings per share		80,610		35,434			33,802
Dilutive securities		3,044		3,055			3,602
Convertible preferred stock		—		42,262			41,450
Denominator for diluted earnings per share		83,654		80,751			78,854
Basic earnings per share	$	1.83	$	3.00		$	2.17
Diluted earnings per share		1.76		1.34			1.13