Note 12 - Stock-based Compensation (Tables)

6 Months Ended

Jun. 30, 2017

Notes Tables

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]

	201 7			201 6
Risk –free interest rate		2.08	%		0.89	%
Expected volatility		16.6	%		15.8	%
Expected life, in years		4.8			2.2
Expected dividend yield		3.10	%		3.09	%

Share-based Compensation, Stock Options, Activity [Table Text Block]

	Number of Shares			Weighted Average Exercise Price		Aggregate Intrinsic Value
Options outstanding at January 1, 201 6		621,390		$	48.15	$	–
Options granted		56,291			62.54		–
Options exercised		(499,066	)		47.16		–
Options cancelled		(656	)		46.69		–
Options outstanding at December 31, 2016		177,959			55.48		–
Options granted		1,124,689			72.96		–
Options exercised		(31,992	)		46.54		–
Options cancelled		–			–		–
Options outstanding at June 30, 2017		1,270,656		$	71.18	$	1,854,000
Options exercisable at June 30, 2017		198,467		$	61.54	$	1,854,000

Schedule of Share-based Compensation, Shares Authorized under Stock Option Plans, by Exercise Price Range [Table Text Block]

Options Outstanding June 30, 2017	Exercise Prices				Weighted Average Exercise Price		Weighted Average Remaining Contractual Life in Years
60,000		$47.45	-	$52.93	$	50.88		1.5
1,210,656		$61.25	-	$75.45		72.18		4.5
1,270,656					$	71.18		4.4