Note 12 - Income Taxes (Details Textual) - USD ($) $ in Millions	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018
Effective Income Tax Rate Reconciliation, Percent, Total	19.20%	17.90%
Effective Income Tax Rate Reconciliation, Tax Expense (Benefit), Share-based Payment Arrangement, Amount	$ 6.0
Domestic Tax Authority [Member] \| Internal Revenue Service (IRS) [Member]
Open Tax Year	2015 2016 2017 2018
State and Local Jurisdiction [Member] \| California Franchise Tax Board [Member]
Open Tax Year	2014 2015 2016 2017 2018

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

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Amount of difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying domestic federal statutory income tax rate to pretax income (loss) from continuing operation, attributable to expense for award under share-based payment arrangement. Excludes expense determined to be nondeductible upon grant or after for award under share-based payment arrangement.

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Tax year that remains open to examination under enacted tax laws, in CCYY format.

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