Note 11 - Income Taxes - Components of Income Tax Expense (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current:
Federal									$ 28,788	$ 31,587	$ 36,180
State									22,364	26,396	14,481
Total Current									51,152	57,983	50,661
Deferred:
Federal									11,775	3,738	23,783
State									4,174	(1,734)	7,521
Total Deferred									15,949	2,004	31,304
Total income tax expense	$ 16,345	$ 15,808	$ 12,273	$ 22,675	$ 16,787	$ 12,098	$ 9,738	$ 21,364	$ 67,101	$ 59,987	$ 81,965