Note 2 - Schedule of Adoption of New Revenue Standard Impacted the Consolidated Financial Statements - Income Statement (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended
	Jan. 01, 2018	Mar. 31, 2018	Mar. 31, 2017
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Gross sales		$ 139,130	$ 103,711
Net revenue		141,097	105,006
Cost of goods sold		90,242	58,131
Gross profit		50,855	46,875
Operating profit		30,381	27,594
Provision for income taxes		5,786	5,812
Income from continuing operations		24,249	21,115
Net income		$ 24,058	$ 19,865
Income from continuing operations		$ 0.72	$ 0.63
Accounting Standards Updated 2014-09 [Member] | Effect of Change Higher/(Lower) [Member]
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Gross sales	$ 51,896	$ 37,280
Net revenue		37,280
Cost of goods sold	31,347	20,699
Gross profit		16,581
Operating profit		16,581
Provision for income taxes	$ 4,330	3,171
Income from continuing operations		13,410
Net income		$ 13,410
Income from continuing operations		$ 0.40
Accounting Standards Updated 2014-09 [Member] | Amount Without Adoption of ASC 606 [Member]
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Gross sales		$ 101,850
Net revenue		103,817
Cost of goods sold		69,543
Gross profit		34,274
Operating profit		13,800
Provision for income taxes		2,615
Income from continuing operations		10,839
Net income		$ 10,648
Income from continuing operations		$ 0.32