Note 17 - Stock-based Compensation (Tables)

12 Months Ended

Dec. 31, 2017

Notes Tables

Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table Text Block]

(In thousands)
	2017			2016			2015
Stock-based compensation expense before income taxes	$	2,892		$	2,473		$	2,134
Less: deferred tax benefit		(607	)		(866	)		(747	)
Reduction of net income	$	2,285		$	1,607		$	1,387

Schedule of Share-based Compensation Arrangement by Share-based Payment Award Fair Value Assumptions and Methodology [Table Text Block]

Assumptions	2017			2016			2015
Dividend yield		2.72	%		2.94	%		2.97	%
Expected volatility		19.47	%		19.31	%		22.81	%
Risk free interest rate		2.29	%		1.70	%		1.91	%
Expected life of SARs (in years)		7.0			7.3			7.5

Schedule of Share-based Compensation, Stock Options and Stock Appreciation Rights Award Activity [Table Text Block]

													Weighted
							Weighted		Aggregate		Weighted		average
	Options						average		intrinsic		average		remaining
	and SARs			Exercise			exercise		value		fair		contractual
	( I n thousands)			price			price		( I n thousands)		value		life ( I n years)
At December 31, 2015
Vested and exercisable		656		$14.02	-	19.44	$	15.75	$	6,191	$	3.39		3.7
Unvested		266		15.24	-	24.55		18.66		1,733		3.29		7.7
Total outstanding		922		14.02	-	24.55		16.59		7,924		3.36		4.8
Activity during 2016
SARs granted		88		25.76	-	33.08		25.84		1,866		3.56
Exercised		(272	)	14.02	-	17.89		16.38		4,155		3.73
Forfeited		(3	)	14.02	-	15.84		15.18		60		2.94
At December 31, 2016
Vested and exercisable		475		14.02	-	24.56		15.72		14,820		3.16		4.3
Unvested		260		15.24	-	33.08		21.53		6,623		3.43		7.8
Total outstanding		735		14.02	-	33.08		17.78		21,443		3.26		5.5
Activity during 2017
SARs granted		46		40.00	-	40.00		40.00		–		6.34
Exercised		(77	)	14.02	-	17.89		15.41		1,855		3.18
Forfeited		–			–			–		–		–
At December 31, 2017
Vested and exercisable		490		14.02	-	33.08		16.46		10,408		3.16		4.0
Unvested		214		15.26	-	40.00		26.46		2,515		4.17		7.7
Total outstanding		704		14.02	-	40.00		19.51		12,923		3.47		5.1
Vested year-to-date		93		$15.24	-	33.08	$	19.37	$	1,696	$	3.18

Schedule of Share-based Compensation, Stock Options and Stock Appreciation Rights, Award Expiration Period [Table Text Block]

Expiration	Number of SARs outstanding		SARs exercisable		Weighted average exercise price of SARs outstanding
2018		17		17	$	15.58
2019		40		40		14.76
2020		73		73		14.02
2021		74		74		15.86
2022		117		117		15.25
2023		80		66		15.26
2024		94		56		19.37
202 5		76		30		22.99
202 6		88		17		25.84
2027		45		–		40.00
		704		490	$	19.51

Schedule of Nonvested Share Activity [Table Text Block]

				Grant date
				weighted-
	Number			average cost
Unvested at December 31, 2014		171,139		$	16.63
Shares awarded		52,898			22.99
Restrictions lapsed and shares released to employees/directors		(61,205	)		15.89
Shares forfeited		(6,974	)		18.97
Unvested at December 31, 2015		155,858		$	18.98
Shares awarded		51,122			25.78
Restrictions lapsed and shares released to employees/directors		(49,265	)		17.98
Shares forfeited		(12,480	)		20.69
Unvested at December 31, 2016		145,235		$	21.57
Shares awarded		28,625			44.85
Restrictions lapsed and shares released to employees/directors		(46,797	)		19.79
Shares forfeited		(7,691	)		25.18
Unvested at December 31, 2017		119,372		$	27.62

Schedule of Share-based Compensation, Restricted Stock Units Award Activity [Table Text Block]

			Fair
	Vesting		value at		Expected
Grant	period		grant		shares to
year	in years		date		be awarded
2015		3	$	20.02		43,011
2016		3		22.61		69,161
2017		3		35.66		43,325

Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares to be Issued Upon Exercise and Remaining Shares Available for Future Issuance [Table Text Block]

Plan category (Shares in thousands)	Number of shares to be issued upon exercise /vesting		Weighted averag e exercise price		Shares available for future issuance (a)
Equity compensation plans approved by security holders:
Stock appreciation rights (SARs)		(b)		(b)		303
Restricted common stock		119		N/A		(a)
Performance stock units		(c)		N/A		(a)
Restricted stock units		5		N/A		(a)
Total shares		124				303