Note 10 - Income Taxes - Deferred Income Taxes (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Other benefit obligations	$ 1,890	$ 1,940
Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Share-based Compensation Cost	4,563	4,080
Net operating losses	25,532	1,983
Accrued bonus	2,313	1,826
Reserves	1,134	365
Interest rate swap	22,101	0
Other items	2,104	1,204
Deferred tax assets	59,637	11,398
Property, plant and equipment	201,208	119,851
Goodwill and other intangible assets	159,074	131,765
Prepaid commissions	2,127	1,909
Other items	542	0
Deferred tax liabilities	362,951	253,525
Net deferred income tax liability	$ 303,314	$ 242,127