Note 17 - Stock-based Compensation (Tables)

12 Months Ended

Dec. 31, 2016

Notes Tables

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

(in thousands)
	2016			2015			2014
Stock-based compensation expense before income taxes	$	2,473		$	2,134		$	2,016
Less: deferred tax benefit		(866	)		(747	)		(706	)
Reduction of net income	$	1,607		$	1,387		$	1,310

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

Assumptions	2016			2015			2014
Dividend yield		2.94	%		2.97	%		2.94	%
Expected volatility		19.31	%		22.81	%		23.66	%
Risk free interest rate		1.70	%		1.91	%		2.22	%
Expected life of SARs (years)		7.3			7.5			7.0

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
	(in thousands)			price			price		(in thousands)		value		life (in years)
At December 31, 2014
Vested and exercisable		786		14.02	-	17.89	$	15.89	$	4,981	$	3.57		3.5
Unvested		291		14.02	-	19.44		16.55		1,650		3.05		7.7
Total outstanding		1,077		14.02	-	19.44		16.07		6,631		3.43		4.6
Activity during 2015
SARs granted		75		34.43	-	36.83		22.99		167		3.97
Exercised		(230	)	21.03	-	26.83		16.27		1,970		3.85
Forfeited		-			0			-		-		-
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
Vested year-to-date		92		$15.24	-	24.56	$	17.46	$	2,726	$	3.14

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

Expiration	Number of options and SARs outstanding		Options and SARs exercisable		Weighted average exercise price of options and SARs outstanding
2017		4		4	$	17.89
2018		43		43		15.58
2019		53		53		14.76
2020		79		79		14.02
2021		84		84		15.85
2022		134		107		15.25
2023		80		52		15.26
2024		94		38		19.37
2025		76		15		22.99
2026		88		-		25.84
		735		475	$	17.78

Schedule of Nonvested Share Activity [Table Text Block]

				Grant date
				weighted-
	Number			average cost
Unvested at December 31, 2013		186,834		$	15.18
Shares awarded		59,595			19.41
Restrictions lapsed and shares released to employees/directors		(67,086	)		15.13
Shares forfeited		(8,204	)		15.85
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

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
2014		3	$	17.61		50,025
2015		3		20.02		51,910
2016		3		22.61		38,037

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		Weighted average exercise price		Shares available for future issuance (a)
Equity compensation plans approved by security holders:
Stock options		4	$	17.89		408
Stock appreciation rights (SARs)	(b)			(b)	(a)
Restricted common stock		145		N/A	(a)
Performance stock units	(c)			N/A	(a)
Restricted stock units		7		N/A	(a)
Total shares		156				408