Note 1 - Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2016

Notes Tables

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

	20 16			20 15			20 14
	(In thousands)
Amounts charged against income, before income tax benefit	$	1,929		$	1,383		$	742
Amount of related income tax benefit		(704	)		(505	)		(269	)
Total impact to net income	$	1,225		$	878		$	473

Fair Value, by Balance Sheet Grouping [Table Text Block]

	December 31, 2016		December 31, 201 5
	(In thousands)
Total carrying amount of long-term debt	$	3,540	$	5,739
Estimated fair value of long-term debt	$	3,533	$	5,708

Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]

	201 6						201 5						201 4
	Class A			Class B			Class A			Class B			Class A		Class B
	(In thousands, except per share data)
Numerator for net income per share - basic:
Net income	$	10,178		$	10,341		$	8,759		$	8,851		$	9,062	$	9,094
Allocation of distributed and undistributed income to unvested restricted stock shareholders		(88	)		(88	)		(76	)		(77	)		--		--
Net income attributa ble to common shareholders	$	10,090		$	10,253		$	8,683		$	8,774		$	9,062	$	9,094
Denominator for net income per share - basic:
Weighted average common shares outstanding - basic		20,713			3,505			20,741			3,478			20,764		3,473
Net income per share - basic	$	0.49		$	2.93		$	0.42		$	2.52		$	0.44	$	2.62
Numerator for net income per share - diluted:
Net inco me attributable to common shareholders for basic computation	$	10,090		$	10,253		$	8,683		$	8,774		$	9,062	$	9,094
Denominator for net income per share - diluted:
Weighted average common s hares outstanding - basic		20,713			3,505			20,741			3,478			20,764		3,473
Weighted average effect of dilutive securities – stock options:		324			55			240			44			312		63
Denomi nator for diluted earnings per share – adjusted weighted average shares		21,037			3,560			20,981			3,522			21,076		3,536
Net income per share - diluted	$	0.48		$	2.88		$	0.41		$	2.49		$	0.43	$	2.57

Fair Value, Measurements, Recurring [Member]

Notes Tables

Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]

	Level 1		Level 2		Level 3		Total
	(In thousands)
As of December 31, 2016
Money Market Funds	$	11,200	$	--	$	--	$	11,200
Commercial Paper		--		21,450		--		21,450
Total Cash Equivalents	$	11,200	$	21,450	$	--	$	32,650
As of December 31, 2015
Money Market Funds	$	8,954	$	--	$	--	$	8,954
Commercial Paper		--		30,872		--		30,872
Total Cash Equivalents	$	8,954	$	30,872	$	--	$	39,826