Note 9 - Dividends and Dividend Equivalents (Tables)

12 Months Ended

Dec. 31, 2017

Notes Tables

Dividends Declared [Table Text Block]

	Year Ended December 31,
	2017		2016		2015
Dividend declared per share	$	0.80	$	0.80	$	0.80
Total amount	$	33,145	$	32,434	$	31,618