Note 10 - Income Taxes (Details) - Income Tax Provisions - 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
Federal:
Current									$ 25,319	$ 18,052	$ 17,808
Deferred									(3,476)	2,860	(464)
Total federal tax provision									21,843	20,912	17,344
State and Local:
Current									7,059	6,369	5,828
Deferred									(1,735)	1,292	(216)
Total state and local tax provision									5,324	7,661	5,612
Total income tax provision	$ 5,439	$ 6,661	$ 9,521	$ 5,546	$ 6,988	$ 7,060	$ 7,598	$ 6,927	$ 27,167	$ 28,573	$ 22,956