Note 5 - Credit Facility and Convertible Debentures (Details Textual) - USD ($) $ in Thousands				3 Months Ended				12 Months Ended
	Jul. 31, 2019	Apr. 15, 2019	May 31, 2018	Sep. 30, 2019	[1]	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Repayments of Lines of Credit								$ (0)	$ 68,568
Interest Expense, Debt, Total				$ 5,806		$ 5,682	$ 2,535	(0)	14,023
Debt Instrument, Gain (Loss) from Covenant Liability									5,100
Interest Paid, Excluding Capitalized Interest, Operating Activities								0	$ 11,500
Revolving Credit Facility [Member]
Debt Instrument, Debt Covenants, Cash and Cash Equivalent Threshold								50,000
Revolving Credit Facility [Member] | Line of Credit [Member]
Interest Expense, Debt, Total								$ 14,000
Debt Instrument, Interest Rate, Effective Percentage								15.10%
Interest Paid, Excluding Capitalized Interest, Operating Activities								$ 11,500
Credit Facility [Member] | Revolving Credit Facility [Member] | Payable on the Last Day of the One, Two or Three Month Interest Period [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument, Basis Spread on Variable Rate			8.50%
Credit Facility [Member] | Revolving Credit Facility [Member] | Payable on the Last Day of the One, Two or Three Month Interest Period [Member] | London Interbank Offered Rate (LIBOR) [Member] | Minimum [Member]
LIBOR Floor Rate			1.00%
Credit Facility [Member] | Revolving Credit Facility [Member] | Payable Monthly in Arrears [Member]
Debt Instrument, Basis Spread on Variable Rate			2.00%
Credit Facility [Member] | Revolving Credit Facility [Member] | Payable Monthly in Arrears [Member] | Minimum [Member]
Debt Instrument, Interest Rate, Stated Percentage			7.50%
Credit Facility [Member] | Revolving Credit Facility [Member] | Payable Monthly in Arrears [Member] | Fed Funds Effective Rate Overnight Index Swap Rate [Member]
Debt Instrument, Basis Spread on Variable Rate			0.50%
Credit Facility [Member] | Revolving Credit Facility [Member] | Payable Monthly in Arrears [Member] | Prime Rate [Member]
Debt Instrument, Basis Spread on Variable Rate			1.00%
Amended Credit Facility [Member]
Debt Instrument, Debt Covenants, Cash and Cash Equivalent Threshold			$ 50,000							$ 50,000
Repayments of Lines of Credit		$ 24,000
Line of Credit Facility, Periodic Payment, Interest		$ 2,900
Extinguishment of Debt, Amount	$ 44,500
Interest Expense, Debt, Total	$ 4,100
Long-term Line of Credit, Repayment Feature, Noncurrent			$ 500

[1] The three months ended December 31, 2019 includes equity income of $1.4 million related to an equity method investment that should have been recorded during the three months ended September 30, 2019. There was no impact on the full year results.