Earnings Per Share

6 Months Ended

Jun. 30, 2011

Earnings Per Share [Abstract]

Earnings Per Share

2.  Earnings Per Share

Basic net income per common share is computed by dividing net income by the weighted average number of shares of common stock outstanding. Diluted net income per common share is computed by dividing net income by the weighted average number of shares of common stock outstanding plus other potentially dilutive securities. Restricted shares and restricted share units subject to performance and/or market conditions are only included in the calculation of diluted net income per common share if all of the necessary performance and/or market conditions have been satisfied assuming the current reporting period were the end of the performance period and the impact is not anti-dilutive. All potential dilutive securities are determined by applying the treasury stock method. The following table sets forth the calculations of basic and diluted net income per share:

	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2011		2010		2011		2010
Basic net income per share:
Net income	$	44,294	$	67,213	$	114,771	$	109,395
Weighted average number of common shares outstanding		48,419,556		50,296,209		48,342,756		50,422,564
Basic net income per share	$	0.91	$	1.34	$	2.37	$	2.17
Diluted net income per share:
Net income	$	44,294	$	67,213	$	114,771	$	109,395
Weighted average number of common shares outstanding		48,419,556		50,296,209		48,342,756		50,422,564
Dilutive effect of stock options and non-vested stock awards		1,764,664		1,021,835		1,813,532		813,375
Dilutive effect of assumed conversion of the 2.0% Convertible Senior Notes		2,196,048		—		1,818,377		—
Dilutive effect of warrants		1,161,100		—		683,638		—
Weighted average number of common shares and dilutive potential common shares outstanding		53,541,368		51,318,044		52,658,303		51,235,939
Diluted net income per share	$	0.83	$	1.31	$	2.18	$	2.14

Potential common stock equivalents representing 4,835 shares and 2,431 shares for the three and six months ended June 30, 2011, respectively, were not included in the computation of diluted net income per share because to do so would have been anti-dilutive. Potential common stock equivalents representing 883,010 shares and 1,525,327 shares for the three and six months ended June 30, 2010, 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 conversion of the Company’s 2.0% Convertible Senior Notes (the “2.0% Convertible Senior Notes”) (See Note 9) were not included in the computation of diluted net income per share for the three and six months ended June 30, 2010 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 three and six months ended June 30, 2010 because to do so would have been anti-dilutive.