Note 12 - Income Taxes (Details Textual) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended	12 Months Ended
	Apr. 30, 2015	Jun. 30, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Apr. 30, 2011
Undistributed Earnings of Foreign Subsidiaries			$ 284,800	$ 214,300
Deferred Tax Assets, Valuation Allowance			27,354	18,614
Increase in Federal R&D Credit			2,200
Unrecognized Tax Benefits			14,431	12,093	$ 16,406	$ 14,922
Unrecognized Tax Benefits that Would Impact Effective Tax Rate			3,500	2,700
Unrecognized Tax Benefits, Interest on Income Taxes Accrued			300	$ 200
Income Tax Examination, Liability (Refund) Adjustment from Settlement with Taxing Authority							$ 10,500
Tax Adjustments, Settlements, and Unusual Provisions		$ 2,700
Income Tax Examination, Tax Payment		1,600
Income Tax Examination, Interest Expense		$ 1,100
State and Local Jurisdiction [Member]
Operating Loss Carryforwards			20,300
Tax Credit Carryforward, Amount			18,300
State and Local Jurisdiction [Member] | Additional Paid-in Capital [Member]
Operating Loss Carryforwards			20,300
Tax Credit Carryforward, Amount			1,800
Domestic Tax Authority [Member]
Operating Loss Carryforwards			0
Tax Credit Carryforward, Amount			$ 17,800
Domestic Tax Authority [Member] | Internal Revenue Service (IRS) [Member]
Income Tax Examination, Year under Examination			2014
Income Taxes Paid	$ 1,200		$ 100
Interest Paid			$ 1,000
Domestic Tax Authority [Member] | Internal Revenue Service (IRS) [Member] | Earliest Tax Year [Member]
Income Tax Examination, Year under Examination			2005
Domestic Tax Authority [Member] | Internal Revenue Service (IRS) [Member] | Latest Tax Year [Member]
Income Tax Examination, Year under Examination			2007
Domestic Tax Authority [Member] | Additional Paid-in Capital [Member]
Tax Credit Carryforward, Amount			$ 8,100