Earnings Per Share (Tables)

12 Months Ended

Dec. 31, 2014

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 years ended December 31 (in thousands, except per share data):

	2014		2013		2012
Net income	$	368,707	$	284,501	$	216,199
Denominator for basic earnings per share		84,317		81,793		83,328
Dilutive securities		2,665		2,862		2,408
Denominator for diluted earnings per share		86,982		84,655		85,736
Basic earnings per share	$	4.37	$	3.48	$	2.59
Diluted earnings per share		4.24		3.36		2.52