Note 5 - Stockholders' Equity (Tables)

9 Months Ended

Sep. 30, 2016

Notes Tables

Class of Treasury Stock [Table Text Block]

	Repurchases Occurring in the Nine Months Ended September 30, 2016				Cumulative Repurchases as of September 30, 2016
	Shares		Average Price		Shares		Average Price
2011 Share Repurchase Authorization		599,123	$	79.21		2,327,636	$	51.09
2016 Share Repurchase Authorization		666,475	$	78.90		666,475	$	78.90

Dividends Declared [Table Text Block]

	Three Months Ended September 30,				Nine Months Ended September 30,
	2016		2015		2016		2015
Dividend amount per share	$	0.25	$	0.20	$	0.70	$	0.56
Total amount of dividend (in thousands)		6,299		5,257		17,823		14,739