Note 7 - Income Taxes - Federal and State Income Tax Expense (Benefit) Summary (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Federal		$ 4,633	$ 0	$ 0
State and local		3,261	2,730	1,259
State and local - reserve for uncertain tax positions		757	(698)	(581)
Current income tax expense (benefit)		8,651	2,032	678
Federal(1)	[1]	(81,666)	38,214	24,067
State and local		4,341	3,172	1,703
Deferred income tax (benefit) expense		(77,325)	41,386	25,770
Income tax (benfit) expense as recorded		$ (68,674)	$ 43,418	$ 26,448

[1] Includes a federal tax benefit of $146.0 million from the restatement of deferred taxes resulting from the reduction of the corporate tax rate due to the enactment of the TCJA.