Note 4 - Long-term Debt - Long-term Debt Summary (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Long-term Debt, Gross	$ 3,967,000	$ 2,570,000
Long-term debt, less deferred financing costs	3,896,000	2,549,000
Less current portion	(14,000)
Long-term debt, less current portion and deferred financing costs	3,882,000	2,549,000
Borrowing availability under Revolving Credit Facility	200,000	100,000
The 2017 Senior Credit Facility [Member]
Long-term Debt, Gross		595,000
Unamortized deferred loan costs		(9,000)
The 2019 Senior Credit Facility [Member]
Long-term Debt, Gross	1,992,000
Unamortized deferred loan costs	(49,000)
2024 Notes [Member]
Long-term Debt, Gross	525,000	525,000
Unamortized deferred loan costs	(6,000)	(6,000)
2026 Notes [Member]
Long-term Debt, Gross	700,000	700,000
Unamortized deferred loan costs	(8,000)	(8,000)
Unamortized premium	4,000	4,000
2027 Notes [Member]
Long-term Debt, Gross	750,000	750,000
Unamortized deferred loan costs	$ (12,000)	$ (2,000)