Note 11 - Long-Term Debt Schedule of Convertible Debt (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Debt Instrument [Line Items]
Net carrying amount		$ 1,008,777		$ 1,069,537
Equity component of currently redeemable convertible senior notes		883		0
Convertible Senior Notes Due 2017
Debt Instrument [Line Items]
Debt Instrument, Convertible, Carrying Amount of Equity Component		5,000		5,000
Net carrying amount		21,303		20,947
Equity component of currently redeemable convertible senior notes		883		0
Convertible Senior Notes Due 2019
Debt Instrument [Line Items]
Debt Instrument, Convertible, Carrying Amount of Equity Component				13,100
Net carrying amount		0		62,013
Equity component of currently redeemable convertible senior notes		0		0
Convertible Debt | Convertible Senior Notes Due 2017
Debt Instrument [Line Items]
Principal amount of convertible debt in liabilities		22,233		22,233
Less: Debt discount, net (1)	[1]	(883)		(1,221)
Less: Debt issuance costs (1)	[1]	(47)		(65)
Net carrying amount		21,303		20,947
Contractual interest expense (benefit)	[2]	167	$ 372
Amortization of debt issuance costs		18	37
Amortization of debt discount		338	708
Total interest expense (benefit)	[2]	523	1,117
Convertible Debt | Convertible Senior Notes Due 2019
Debt Instrument [Line Items]
Principal amount of convertible debt in liabilities		0		68,024
Less: Debt discount, net (1)	[1]	0		(5,461)
Less: Debt issuance costs (1)	[1]	0		(550)
Net carrying amount		0		$ 62,013
Contractual interest expense (benefit)	[2]	(510)	2,013
Amortization of debt issuance costs		16	293
Amortization of debt discount		163	2,909
Total interest expense (benefit)	[2]	$ (331)	$ 5,215

[1] Included within long-term debt and is being amortized over the life of the convertible notes.

[2] Interest expense (benefit) represents expense incurred, net of adjustments to accruals previously recorded.