Note 7 - Income Taxes - Current and Deferred Income Tax Expense (Benefit) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Current:
Federal	$ 138,952	$ 87,977	$ 22,904
State and local	28,094	20,981	26,738
Current income taxes, total	167,046	108,958	49,642
Deferred:
Federal	(2,392)	51,229	97,670
State and local	(4,664)	4,388	3,921
Deferred income taxes, total	(7,056)	55,617	101,591
Total tax expense/(benefit)	$ 159,990	$ 164,575	$ 151,233