Note 11 - Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2015

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

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

	For three months ended						For nine months ended
(in thousands)	September 30,						September 30,
	2015			2014			2015			2014
Stock-based compensation expense before income taxes	$	566		$	691		$	1,561		$	1,459
Less: deferred tax benefit		(198	)		(242	)		(546	)		(510	)
Reduction of net income	$	368		$	449		$	1,015		$	949

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

	2015			2014
Dividend yield		2.97	%		2.94	%
Expected volatility		22.81	%		23.66	%
Risk free interest rate		1.91	%		2.22	%
Expected life of SARs (in years)		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		524		$	21.03	-	26.83	$	23.84	$	4,981	$	5.35		3.5
Unvested		194			21.03	-	29.16		24.83		1,650		4.57		7.7
Total outstanding		718			21.03	-	29.16		24.11		6,631		5.14		4.6
Granted		50			34.43	-	36.83		34.48		76		5.95
Exercised		(102	)		21.03	-	26.83		24.22		1,186		5.72
Forfeited		-				-			-		-		-
At September 30, 2015
Vested and exercisable		489			21.03	-	29.16		24.38		5,974		5.17		3.6
Unvested		177			22.86	-	36.83		27.99		1,411		4.93		7.9
Total outstanding		666			21.03	-	36.83		26.19	$	7,385		5.11		4.7
Vested year-to-date		67			21.03	-	29.16		23.77	$	817		4.65

Schedule of Nonvested Share Activity [Table Text Block]

				Grant date
				weighted-
	Number			average cost
Unvested at December 31, 2013		124,556		$	22.77
Shares awarded		39,730			29.12
Restrictions lapsed and shares released to employees/directors		(44,724	)		22.69
Shares forfeited		(5,469	)		23.77
Unvested at December 31, 2014		114,093		$	24.95
Shares awarded		34,990			34.43
Restrictions lapsed and shares released to employees/directors		(40,510	)		23.84
Shares forfeited		(3,766	)		28.11
Unvested at September 30, 2015		104,807		$	28.44

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

	Vesting				Expected
Grant	period		Fair		shares to
year	in years		value		be awarded
2013		3	$	20.38		36,792
2014		3		26.42		29,181
2015		3		31.54		19,774