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Note 2 - Summary of Significant Accounting Policies (Details Textual) - USD ($) $ in Thousands		3 Months Ended	12 Months Ended
	Nov. 30, 2017	Dec. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Jan. 01, 2018
Capitalized Computer Software, Net		$ 4,900	$ 4,900	$ 0	$ 0
Advertising Expense			10,700	10,500	10,000
Research and Development Expense			23,560	22,388	18,350
Payments to Acquire Businesses, Net of Cash Acquired			110,533		5,032
Income Tax Expense (Benefit)			22,657	$ 21,514	$ 21,347
Accounting Standards Update 2016-09 [Member]
Income Tax Expense (Benefit)		$ 400	700
Reclassification of Cash Flows Related to Excess Tax Benefits from Financing Activities to Operating Activity [Member] \| Twelve Months Ended December 31, 2016 [Member]
Prior Period Reclassification Adjustment			2,500
Reclassification of Cash Flows Related to Excess Tax Benefits from Financing Activities to Operating Activity [Member] \| Twelve Months Ended December 31, 2015 [Member]
Prior Period Reclassification Adjustment			$ 5,500
Accounting Standards Update 2014-09 [Member] \| Subsequent Event [Member] \| Retained Earnings [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption						$ 1,500
Rapid [Member]
Business Combination, Consideration Transferred	$ 121,869
Payments to Acquire Businesses, Net of Cash Acquired	110,533
Business Combination, Consideration Transferred, Equity Interests Issued and Issuable	$ 11,336
Building [Member]
Property, Plant and Equipment, Useful Life			39 years
Minimum [Member]
Property, Plant and Equipment, Useful Life			3 years
Finite-Lived Intangible Asset, Useful Life			2 years
Minimum [Member] \| Equipment [Member]
Property, Plant and Equipment, Useful Life			3 years
Minimum [Member] \| Office Furniture And Equipment [Member]
Property, Plant and Equipment, Useful Life			3 years
Minimum [Member] \| Computer Equipment [Member]
Property, Plant and Equipment, Useful Life			3 years
Minimum [Member] \| Land, Buildings and Improvements [Member]
Property, Plant and Equipment, Useful Life			10 years
Maximum [Member]
Property, Plant and Equipment, Useful Life			39 years
Finite-Lived Intangible Asset, Useful Life			10 years
Maximum [Member] \| Equipment [Member]
Property, Plant and Equipment, Useful Life			15 years
Maximum [Member] \| Office Furniture And Equipment [Member]
Property, Plant and Equipment, Useful Life			7 years
Maximum [Member] \| Computer Equipment [Member]
Property, Plant and Equipment, Useful Life			5 years
Maximum [Member] \| Land, Buildings and Improvements [Member]
Property, Plant and Equipment, Useful Life			39 years