Earnings Per Share

12 Months Ended

Dec. 31, 2012

Earnings Per Share [Abstract]

Earnings Per Share

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,
	2012			2011			2010
Net income	$	385,555		$	258,966		$	221,393
Less:
Net income attributable to participating securities	(2,160		)	(2,310		)	(2,230		)
Net income attributable to common shareholders	$	383,395		$	256,656		$	219,163

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,
	2012		2011		2010
Weighted average common shares—basic	66,289,429		65,927,421		65,472,875
Plus incremental shares from:
Assumed exercise of options	352,066		372,737		203,789
Weighted average common shares—diluted	66,641,495		66,300,158		65,676,664
Earnings per share:
Basic	$	5.78	$	3.89	$	3.35
Diluted	$	5.75	$	3.87	$	3.34

Excluded from the computation of diluted earnings per share for the years ended December 31, 2012, 2011 and 2010 are options to purchase 99,012, 141,335 and 433,403 shares of common stock, respectively. These options were outstanding during the periods reported but were excluded because the effect of including them would have been antidilutive.