Note 7 - Income Taxes - Current and Deferred Income Tax Expense (Benefit) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current:
Federal	$ 22,904	$ 134,284	$ 191,422
State and local	26,738	23,456	21,871
Current income taxes, total	49,642	157,740	213,293
Deferred:
Federal	97,670	(261,592)	45,846
State and local	3,921	12,828	4,568
Deferred income taxes, total	101,591	(248,764)	50,414
Total tax expense/(benefit)	$ 151,233	$ (91,024)	$ 263,707