Note 9 - Income Taxes (Details) - Income Tax Reconcilliation (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Reconcilliation [Abstract]
Computed "expected" income tax expense	$ 11,404	$ 4,462	$ 4,340
State income taxes, net of federal income tax effect	1,075	421	409
Per diem allowances	2,304	2,422	2,550
Tax contingency accruals	(104)	(496)	(444)
Valuation allowance (release), net	18	684	(251)
Tax credits	(112)	(250)	(407)
Other, net	189	260	138
Actual income tax expense	$ 14,774us-gaap_IncomeTaxExpenseBenefit	$ 7,503us-gaap_IncomeTaxExpenseBenefit	$ 6,335us-gaap_IncomeTaxExpenseBenefit

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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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