Note 14 - Financing Agreement - Debt Instrument Redemption (Details)	12 Months Ended
	Dec. 31, 2020
Senior Notes due December 15, 2024 [Member] | Debt Instrument, Redemption, Period One [Member]
Debt Instrument, Redemption Price, Percentage	101.833%
Senior Notes due December 15, 2024 [Member] | Debt Instrument, Redemption, Period Two [Member]
Debt Instrument, Redemption Price, Percentage	100.917%
Senior Notes due December 15, 2024 [Member] | Debt Instrument, Redemption, Period Three [Member]
Debt Instrument, Redemption Price, Percentage	100.00%
Senior Notes due December 15, 2024 [Member] | Debt Instrument, Redemption, Period Four [Member]
Debt Instrument, Redemption Price, Percentage	100.00%
Senior Notes due April 15, 2025 [Member] | Debt Instrument, Redemption, Period One [Member]
Debt Instrument, Redemption Price, Percentage	104.313%
Senior Notes due April 15, 2025 [Member] | Debt Instrument, Redemption, Period Two [Member]
Debt Instrument, Redemption Price, Percentage	102.875%
Senior Notes due April 15, 2025 [Member] | Debt Instrument, Redemption, Period Three [Member]
Debt Instrument, Redemption Price, Percentage	101.438%
Senior Notes due April 15, 2025 [Member] | Debt Instrument, Redemption, Period Four [Member]
Debt Instrument, Redemption Price, Percentage	100.00%
Senior Notes due April 15, 2025 [Member] | Debt Instrument, Redemption, Period Five [Member]
Debt Instrument, Redemption Price, Percentage	100.00%
Senior Notes due June 1, 2026 [Member] | Debt Instrument, Redemption, Period One [Member]
Debt Instrument, Redemption Price, Percentage	100.00%
Senior Notes due June 1, 2026 [Member] | Debt Instrument, Redemption, Period Two [Member]
Debt Instrument, Redemption Price, Percentage	103.25%
Senior Notes due June 1, 2026 [Member] | Debt Instrument, Redemption, Period Three [Member]
Debt Instrument, Redemption Price, Percentage	102.167%
Senior Notes due June 1, 2026 [Member] | Debt Instrument, Redemption, Period Four [Member]
Debt Instrument, Redemption Price, Percentage	101.083%
Senior Notes due June 1, 2026 [Member] | Debt Instrument, Redemption, Period Five [Member]
Debt Instrument, Redemption Price, Percentage	100.00%
Senior Notes due June 1, 2026 [Member] | Debt Instrument, Redemption, Period Six [Member]
Debt Instrument, Redemption Price, Percentage	100.00%
Senior Notes due November 15, 2027 [Member]
Debt Instrument, Redemption Price, Percentage	100.00%
Senior Notes due November 15, 2027 [Member] | Debt Instrument, Redemption, Period Three [Member]
Debt Instrument, Redemption Price, Percentage	102.688%
Senior Notes due November 15, 2027 [Member] | Debt Instrument, Redemption, Period Four [Member]
Debt Instrument, Redemption Price, Percentage	101.344%
Senior Notes due November 15, 2027 [Member] | Debt Instrument, Redemption, Period Five [Member]
Debt Instrument, Redemption Price, Percentage	100.00%
Senior Notes due November 15, 2027 [Member] | Debt Instrument, Redemption, Period Six [Member]
Debt Instrument, Redemption Price, Percentage	100.00%
Senior Notes due November 15, 2027 [Member] | Debt Instrument, Redemption, Period Seven [Member]
Debt Instrument, Redemption Price, Percentage	100.00%
Senior Notes due June 15, 2028 [Member]
Debt Instrument, Redemption Price, Percentage	100.00%
Senior Notes due June 15, 2028 [Member] | Debt Instrument, Redemption, Period Four [Member]
Debt Instrument, Redemption Price, Percentage	102.813%
Senior Notes due June 15, 2028 [Member] | Debt Instrument, Redemption, Period Five [Member]
Debt Instrument, Redemption Price, Percentage	101.406%
Senior Notes due June 15, 2028 [Member] | Debt Instrument, Redemption, Period Six [Member]
Debt Instrument, Redemption Price, Percentage	100.00%
Senior Notes due June 15, 2028 [Member] | Debt Instrument, Redemption, Period Seven [Member]
Debt Instrument, Redemption Price, Percentage	100.00%
Senior Notes due June 15, 2028 [Member] | Debt Instrument, Redemption, Period Eight [Member]
Debt Instrument, Redemption Price, Percentage	100.00%