Note 12 - Fair Value Measurements (Details Textual) $ in Millions	Dec. 20, 2011	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Oct. 15, 2018
Available-for-sale Securities, Total		$ 19.5
Debt Security Interest Rate Stated Percentage		7.50%
Debt Security, Available-For-Sale, Fair Value Discount Amount		$ 2.7	$ 2.8
Business Combination Contingent Consideration Arrangements, Payment To Option Holder Percentage Of Ebitda	1.00%
Other Long-Term Debt [Member]
Long-term Debt, Term				96 months
Prepaid Expenses and Other Current Assets [Member]
Available-for-sale Securities, Current, Total		0.6	0.5
Other Assets [Member]
Available-for-sale Securities, Total		15.6	15.3
Accounts Payable and Accrued Liabilities [Member]
Business Combination, Contingent Consideration, Liability, Current		0.9	0.8
Other Liabilities [Member]
Business Combination, Contingent Consideration, Liability, Total		$ 0.8	$ 1.6
Measurement Input, Discount Rate [Member]
Debt Securities, Available-for-sale, Measurement Input		10.5	0.112
Business Combination, Contingent Consideration, Liability, Measurement Input		0.062	0.068