Note 3 - Recent Accounting Pronouncements (Details Textual) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Jan. 01, 2020	Dec. 31, 2019
Retained Earnings (Accumulated Deficit), Ending Balance	$ 1,681,345		$ 1,659,153
Cumulative Effect, Period of Adoption, Adjustment [Member] | Accounting Standards Update 2016-13 [Member] | Minimum [Member]
Retained Earnings (Accumulated Deficit), Ending Balance		$ 14,000
Accounts Receivable, Allowance for Credit Loss, Ending Balance		20,000
Accounts Receivable, Credit Loss Expense (Reversal)	5,000
Cumulative Effect, Period of Adoption, Adjustment [Member] | Accounting Standards Update 2016-13 [Member] | Maximum [Member]
Retained Earnings (Accumulated Deficit), Ending Balance		18,000
Accounts Receivable, Allowance for Credit Loss, Ending Balance		$ 25,000
Accounts Receivable, Credit Loss Expense (Reversal)	$ 15,000