Earnings Per Share (Tables)

12 Months Ended

Dec. 31, 2017

Earnings Per Share [Abstract]

Schedule Of Earnings Per Share Basic And Diluted By Common Class [Table Text Block]

The following table sets forth the computation of basic and diluted earnings per share on net income (in thousands, except per share information):

	2017		2016		2015
Earnings:
Net income (numerator for basic and diluted calculations)	$	1,822,181	$	701,443	$	502,166
Shares:
Weighted average outstanding shares (denominator for basic calculations)	64,427		64,274		66,553
Equivalent shares from outstanding stock options	1,326		715		739
Diluted shares (denominator for diluted calculations)	65,753		64,989		67,292
Earnings per share:
Basic	$	28.28	$	10.91	$	7.55
Diluted	27.71		10.79		7.46