Earnings Per Share (Tables)

6 Months Ended

Jun. 30, 2013

Earnings Per Share [Abstract]

Summary of Earnings Per Share, Basic and Diluted

The calculation and reconciliation of basic and diluted earnings per share for the three and six months ended June 30 (in thousands, except per share data):

	Three Months Ended June 30,				Six Months Ended June 30,
	2013		2012		2013		2012
Net income	$	73,099	$	54,401	$	137,761	$	96,480
Denominator for basic and diluted earnings per share:
Weighted-average shares outstanding		81,111		82,430		80,912		82,054
Share-based payment awards classified as participating securities		462		864		486		875
Denominator for basic earnings per share		81,573		83,294		81,398		82,929
Dilutive securities		2,888		2,443		2,814		2,522
Denominator for diluted earnings per share		84,461		85,737		84,212		85,451
Basic earnings per share	$	0.90	$	0.65	$	1.69	$	1.16
Diluted earnings per share	$	0.87	$	0.63	$	1.64	$	1.13