Note 8 - Income Taxes (Details) - Reconciliation of Income Tax Expense (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Reconciliation of Income Tax Expense [Abstract]
Statutory federal rate applied to income before income tax expense	$ 27,929	$ 11,002	$ 16,561
Current year permanent items	849	669	825
State and local taxes, net of federal tax benefit	4,050	1,432	4,191
Change in valuation allowance	(696)	(409)	(1,463)
Reserve for uncertain tax positions	(198)	(136)	(1,015)
Other items, net	(198)	589	89
Income tax expense as recorded	$ 31,736us-gaap_IncomeTaxExpenseBenefit	$ 13,147us-gaap_IncomeTaxExpenseBenefit	$ 19,188us-gaap_IncomeTaxExpenseBenefit
Effective income tax rate	39.80%	41.80%	40.60%

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Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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The amount of income tax expense or benefit for the period computed by applying the domestic federal statutory tax rates to pretax income from continuing operations.

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Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to tax exempt income, equity in earnings (loss) of an unconsolidated subsidiary, minority noncontrolling interest income (loss), tax holiday, disposition of a business, disposition of an asset, repatriation of foreign earnings, repatriation of foreign earnings jobs creation act of 2004, increase (decrease) in enacted tax rate, prior year income taxes, increase (decrease) in deferred tax asset valuation allowance, and other adjustments.

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