Earnings per Share (Tables)

9 Months Ended

Sep. 30, 2012

Earnings Per Share [Abstract]

Schedule Of Net Income Attributable To Common Stockholders

	Three Months Ended September 30,						Nine Months Ended September 30,
	2012			2011			2012			2011
Net income	$	86,964		$	67,930		$	290,278		$	232,523
Less:
Net income attributable to participating securities	(452		)	(598		)	(1,682		)	(2,087		)
Net income attributable to common shareholders	$	86,512		$	67,332		$	288,596		$	230,436

Reconciliation Of Denominator For Basic And Diluted Earnings Per Share

The following table reconciles the denominator for the basic and diluted earnings per share computations shown in the consolidated statements of operations:

	Three Months Ended September 30,				Nine Months Ended September 30,
	2012		2011		2012		2011
Weighted average common shares—basic	66,311,958		66,012,102		66,240,225		65,919,892
Plus incremental shares from:
Assumed exercise of options	344,802		369,830		381,295		387,712
Weighted average common shares—diluted	66,656,760		66,381,932		66,621,520		66,307,604
Earnings per share:
Basic	$	1.30	$	1.02	$	4.36	$	3.50
Diluted	$	1.30	$	1.01	$	4.33	$	3.48