Note 6 - Reconciliation of Income Tax Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Computed at federal statutory rate	$ 13,934	$ 9,215	$ 22,946
Computed at federal statutory rate	35.00%	35.00%	35.00%
State and local tax expense, net of federal benefit	$ 1,038	$ 2,973	$ 2,448
State and local tax expense, net of federal benefit	2.60%	11.30%	3.70%
Other, net	$ 310	$ 195	$ 199
Other, net	0.80%	0.70%	0.30%
Income taxes	$ 15,282	$ 12,383	$ 25,593
Effective Income Tax Rate Reconciliation, Percent	38.40%	47.00%	39.00%