Quarterly Financial Data (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2018

QUARTERLY FINANCIAL DATA (UNAUDITED) [Abstract]

Schedule of Quarterly Financial Information [Table Text Block]

	First Quarter		Second Quarter		Third Quarter		Fourth Quarter
2018
Net sales	$	660,821	$	721,996	$	734,846	$	817,923
Gross profit	$	374,933	$	412,625	$	419,254	$	477,566
Net earnings	$	93,304	$	111,468	$	126,653	$	181,186
Basic earnings per common share:
Net earnings	$	3.66	$	4.41	$	5.04	$	7.25
Weighted average number of common shares	25,468,323		25,299,414		25,126,061		24,975,303
Diluted earnings per common share:
Net earnings	$	3.58	$	4.31	$	4.93	$	7.11
Weighted average number of common and common equivalent shares	26,095,647		25,867,383		25,683,365		25,490,270
Market price per share:
High	$	692.30	$	595.14	$	617.94	$	645.33
Low	$	566.87	$	546.43	$	559.44	$	524.03
2017
Net sales	$	594,567	$	653,656	$	698,799	$	778,031
Gross profit	$	343,389	$	375,612	$	400,975	$	455,775
Net earnings	$	92,466	$	101,580	$	104,950	$	76,976
Basic earnings per common share:
Net earnings	$	3.57	$	3.94	$	4.10	$	3.01
Weighted average number of common shares	25,932,112		25,751,374		25,613,433		25,562,542
Diluted earnings per common share:
Net earnings	$	3.48	$	3.84	$	3.99	$	2.93
Weighted average number of common and common equivalent shares	26,586,061		26,439,529		26,303,529		26,229,052
Market price per share:
High	$	486.90	$	601.16	$	635.17	$	689.11
Low	$	414.52	$	473.87	$	571.25	$	606.80