Note 12 - Income Taxes (Details) - Components of Income Tax Expense - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Current:
Federal									$ 31,587	$ 36,180	$ 62,254
State									26,396	14,481	23,295
Total Current									57,983	50,661	85,549
Deferred:
Federal									3,738	23,783	(11,162)
State									(1,734)	7,521	(3,952)
Total Deferred									2,004	31,304	(15,114)
Total income tax expense	$ 16,787	$ 12,098	$ 9,738	$ 21,364	$ 21,021	$ 22,313	$ 20,741	$ 17,890	$ 59,987	$ 81,965	$ 70,435