Earnings Per Share

12 Months Ended

Dec. 31, 2011

Earnings Per Share [Abstract]

Earnings Per Share

14. Earnings per Share

The Company has unvested shares of restricted stock outstanding that are considered participating securities and, therefore, computes basic and diluted earnings per share under the two-class method. Basic earnings per share for the periods are based upon the weighted average number of shares of common stock outstanding during the periods. Diluted earnings per share include the effect of certain stock options.

	Year Ended December 31,
	2011			2010			2009
Net income	$	258,966		$	221,393		$	52,995
Less:
Net income attributable to participating securities		(2,310	)		(2,230	)		(475	)
Net income attributable to common shareholders	$	256,656		$	219,163		$	52,520

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

	Year Ended December 31,
	2011		2010		2009
Weighted average common shares—basic		65,927,421		65,472,875		65,323,101
Plus incremental shares from:
Assumed exercise of options		372,737		203,789		98,289
Weighted average common shares—diluted		66,300,158		65,676,664		65,421,390
Earnings per share:
Basic	$	3.89	$	3.35	$	0.80
Diluted	$	3.87	$	3.34	$	0.80

Excluded from the computation of diluted earnings per share for the years ended December 31, 2011, 2010 and 2009 are options to purchase 141,335, 433,403 and 536,644 shares of common stock, respectively. These options were outstanding during the periods reported but were excluded because the option exercise price was greater than the average market price of the shares.