Note 15 - Income Taxes (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Deferred Tax Liabilities, Undistributed Foreign Earnings	$ 0
Income Tax Expense (Benefit)	$ 21,347,000	$ 18,896,000	$ 16,301,000
Effective Income Tax Rate Reconciliation, Percent	31.50%	31.20%	31.60%
Income Tax Credits and Adjustments			$ 500,000
Effective Income Tax Rate Reconciliation, Tax Credit, Percent			0.90%
Undistributed Earnings of Foreign Subsidiaries	$ 25,800,000
Operating Loss Carryforwards	$ 2,400,000
Operating Loss Carryforwards, Expiration Period	10 years
Operating Loss Carryforwards, Percentage of Taxable Income	65.00%
Deferred Tax Assets, Valuation Allowance	$ 2,625,000	$ 3,048,000
Unrecognized Tax Benefits	$ 2,769,000	$ 1,295,000	$ 695,000