Note 8 - Earnings Per Share (Details) - Calculation of Earnings Per Share (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Common Class A [Member] | Employee Stock Option [Member]
Weighted average effect of dilutive securities:
Share based payment	278	379	310	369
Common Class A [Member] | Restricted Stock [Member]
Weighted average effect of dilutive securities:
Share based payment	24	34	31	34
Common Class A [Member]
Numerator for net income per share - basic:
Allocation of distributed earnings (in Dollars)				$ 1,071
Allocation of undistributed earnings (in Dollars)	2,022	1,717	4,744	2,881
Net income attributable to common shareholders (in Dollars)	2,022	1,717	4,744	3,952
Denominator for net income per share - basic:
Weighted average common shares outstanding - basic	20,771	20,672	20,757	20,671
Net income per share - basic (in Dollars per share)	$ 0.10	$ 0.08	$ 0.23	$ 0.19
Numerator for net income per share - diluted:
Net income attributable to common shareholders for basic computation (in Dollars)	2,022	1,717	4,744	3,952
Weighted average common shares outstanding - basic	20,771	20,672	20,757	20,671
Weighted average effect of dilutive securities:
Weighted average common shares outstanding - diluted	21,073	21,085	21,098	21,074
Net income per share - diluted (in Dollars per share)	$ 0.10	$ 0.08	$ 0.22	$ 0.19
Common Class B [Member] | Employee Stock Option [Member]
Weighted average effect of dilutive securities:
Share based payment	61	65	63	62
Common Class B [Member] | Restricted Stock [Member]
Weighted average effect of dilutive securities:
Share based payment	4	6	5	6
Common Class B [Member]
Numerator for net income per share - basic:
Allocation of distributed earnings (in Dollars)				1,071
Allocation of undistributed earnings (in Dollars)	2,029	1,717	4,761	2,881
Net income attributable to common shareholders (in Dollars)	2,029	1,717	4,761	3,952
Denominator for net income per share - basic:
Weighted average common shares outstanding - basic	3,474	3,445	3,472	3,445
Net income per share - basic (in Dollars per share)	$ 0.58	$ 0.50	$ 1.37	$ 1.15
Numerator for net income per share - diluted:
Net income attributable to common shareholders for basic computation (in Dollars)	$ 2,029	$ 1,717	$ 4,761	$ 3,952
Weighted average common shares outstanding - basic	3,474	3,445	3,472	3,445
Weighted average effect of dilutive securities:
Weighted average common shares outstanding - diluted	3,539	3,516	3,540	3,513
Net income per share - diluted (in Dollars per share)	$ 0.57	$ 0.49	$ 1.34	$ 1.12