Note 1 - Summary of Significant Accounting Policies (Details) - Net Income Per Share Computation (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Employee Stock Option [Member] | Common Class A [Member]
Weighted average effect of dilutive securities:
Dilutive securities	388	492	474
Employee Stock Option [Member] | Common Class B [Member]
Weighted average effect of dilutive securities:
Dilutive securities	61	82	79
Restricted Stock [Member] | Common Class A [Member]
Weighted average effect of dilutive securities:
Dilutive securities	34	37	36
Restricted Stock [Member] | Common Class B [Member]
Weighted average effect of dilutive securities:
Dilutive securities	6	6	6
Common Class A [Member]
Numerator for net income per share - basic:
Allocation of distributed earnings (in Dollars)	$ 1,071	$ 8,681	$ 2,956
Allocation of undistributed earnings (in Dollars)	6,670	(1,147)	2,826
Net income attributable to common shareholders (in Dollars)	7,741	7,534	5,782
Denominator for net income per share - basic:
Weighted average common shares outstanding - basic	20,677	20,325	20,016
Weighted average effect of dilutive securities:
Weighted average common shares outstanding - diluted	21,099	20,854	20,526
Net income per share - diluted (in Dollars per share)	$ 0.37	$ 0.37	$ 0.29
Net income per share - basic (in Dollars per share)	$ 0.37	$ 0.36	$ 0.28
Numerator for net income per share - diluted:
Net income attributable to common shareholders for basic computation (in Dollars)	7,741	7,534	5,782
Common Class B [Member]
Numerator for net income per share - basic:
Allocation of distributed earnings (in Dollars)	1,071	8,681	2,956
Allocation of undistributed earnings (in Dollars)	6,672	(1,147)	2,826
Net income attributable to common shareholders (in Dollars)	7,743	7,534	5,782
Denominator for net income per share - basic:
Weighted average common shares outstanding - basic	3,447	3,388	3,336
Weighted average effect of dilutive securities:
Weighted average common shares outstanding - diluted	3,514	3,476	3,421
Net income per share - diluted (in Dollars per share)	$ 2.20	$ 2.17	$ 1.69
Net income per share - basic (in Dollars per share)	$ 2.25	$ 2.22	$ 1.73
Numerator for net income per share - diluted:
Net income attributable to common shareholders for basic computation (in Dollars)	$ 7,743	$ 7,534	$ 5,782