Note 2 - New Accounting Pronouncements (Details Textual) - USD ($) $ in Thousands		3 Months Ended
	Jan. 01, 2018	Mar. 31, 2018	Dec. 31, 2017
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period		2 years
Deferred Costs, Total			$ 49,834
Accounting Standards Update 2014-09 [Member]
Cumulative Effect on Retained Earnings, Net of Tax, Total	$ 24,000
Accounting Standards Update 2016-16 [Member]
Cumulative Effect on Retained Earnings, Net of Tax, Total		1,800
Deferred Costs, Total		49,800
Deferred Tax Assets, Net, Noncurrent		51,600
Accounting Standards Update 2016-15 [Member] | Reclassifcation of Cash Paid From Investing Activities to Financing Activities [Member]
Prior Period Reclassification Adjustment			$ 8,000
Product Segment [Member]
Revenue, Remaining Performance Obligation, Amount		$ 211,000