Earnings Per Share

12 Months Ended

Dec. 31, 2011

Earnings Per Share [Abstract]

Earnings Per Share

(16) Earnings Per Share

The following table sets forth the calculation of basic and diluted net income per share:

	Years Ended December 31,
	2011		2010		2009
Basic net income per share:
Net income	$	195,621	$	273,371	$	149,279
Weighted average number of common shares outstanding		47,731,265		49,522,202		51,647,267
Basic net income per share	$	4.10	$	5.52	$	2.89
Diluted net income per share:
Net income	$	195,621	$	273,371	$	149,279
Weighted average number of common shares outstanding		47,731,265		49,522,202		51,647,267
Dilutive effect of stock options and non-vested stock awards		1,593,018		1,085,806		662,001
Dilutive effect of assumed conversion of the 2.0% Convertible Senior Notes		1,525,271		—		—
Dilutive effect of warrants		313,554		—		—
Weighted average number of common shares and dilutive potential common shares outstanding		51,163,108		50,608,008		52,309,268
Diluted net income per share	$	3.82	$	5.40	$	2.85

Potential common stock equivalents representing 50,857 shares, 895,899 shares and 2,676,447 shares for the years ended December 31, 2011, 2010 and 2009, respectively, were not included in the computation of diluted net income per share because to do so would have been anti-dilutive.

The shares issuable upon the conversion of the Company’s 2.0% Convertible Senior Notes (see Note 9) were not included in the computation of diluted net income per share for the years ended December 31, 2010 and 2009 because to do so would have been anti-dilutive.

The Company’s warrants to purchase shares of its common stock (see Note 9) were not included in the computation of diluted net income per share for the years ended December 31, 2010 and 2009 because to do so would have been anti-dilutive.