Earnings Per Share (Tables)

3 Months Ended

Mar. 31, 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 months ended March 31 (in thousands, except per share data):

	Three Months Ended March 31,
	2013		2012
Net income	$	64,662	$	42,079
Denominator for basic and diluted earnings per share:
Weighted-average shares outstanding		80,746		81,702
Share-based payment awards classified as participating securities		476		863
Denominator for basic earnings per share		81,222		82,565
Dilutive securities		2,738		2,599
Denominator for diluted earnings per share		83,960		85,164
Basic earnings per share	$	0.80	$	0.51
Diluted earnings per share	$	0.77	$	0.49