Earnings Per Share (Tables)

6 Months Ended

Jun. 30, 2017

Earnings Per Share [Abstract]

Reconciliation Between Basic and Diluted Earnings Per Share

A reconciliation between basic and diluted earnings per share is as follows (in thousands, except per share data):

	Quarter Ended June 30,				Six Months Ended June 30,
	2017		2016		2017		2016
Net income for basic and diluted earnings per share	$	369,526	$	229,905	$	584,252	$	329,045
Weighted-average common shares outstanding	215,085		215,265		214,978		216,089
Dilutive effect of stock options, performance share awards and restricted stock awards	977		866		966		951
Diluted weighted-average shares outstanding	216,062		216,131		215,944		217,040
Basic earnings per share	$	1.72	$	1.07	$	2.72	$	1.52
Diluted earnings per share	$	1.71	$	1.06	$	2.71	$	1.52