Note 1 - Summary of Significant Interim Accounting Policies (Details Textual)	3 Months Ended
	Mar. 31, 2018 USD ($) shares	Mar. 31, 2017 USD ($)	Mar. 01, 2018 USD ($)	Jan. 01, 2018 USD ($)	Dec. 31, 2017 USD ($)	Jun. 30, 2017 USD ($)	Jan. 03, 2017 USD ($)	Jul. 01, 2014 USD ($)
Subsidiary of Limited Liability Company or Limited Partnership, Ownership Interest	99.00%
Amortization of Intangible Assets, Total	$ 800,000	$ 600,000
Advertising Expense	100,000	100,000
Selling, General and Administrative Expense, Total	$ 21,182,000	17,429,000
Derivative, Notional Amount								$ 14,300,000
Number of Reportable Segments	3
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant | shares	3,507,469
Revenue from Contract with Customer, Excluding Assessed Tax, Total	$ 73,087,000	60,987,000
Revenue, Remaining Performance Obligation, Amount	0
Contract with Customer, Asset, Net, Current, Total	47,098,000			$ 43,300,000
Accounting Standards Update 2014-09 [Member]
Revenue from Contract with Customer, Excluding Assessed Tax, Total	$ 3,700,000
Cumulative Tax Adjustments Payment, Period	4 years
Accounting Standards Update 2014-09 [Member] | Retained Earnings [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption				$ 11,200,000
Interest Rate Swap [Member]
Derivative, Notional Amount	$ 18,000,000		$ 18,000,000
Interest Rate Swap [Member] | Other Current Liabilities [Member]
Derivative Liability, Total	100,000
Foreign Exchange Contract [Member]
Derivative, Notional Amount							$ 1,800,000
Foreign Exchange Contract [Member] | Other Current Liabilities [Member]
Derivative Liability, Total						$ 100,000
Shipping and Handling [Member]
Selling, General and Administrative Expense, Total	$ 2,700,000	$ 2,800,000