Note 13 - Income Taxes - Summary of Deferred Tax Assets (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Employee wages and other benefits	$ 49.9	$ 54.9
Lease liabilities	55.4	53.3
Net operating loss carryover	9.4	12.0
Interest expense	31.0	31.1
Book/tax energy basis difference	0.0	112.2
Other	17.1	22.0
Total	162.8	285.5
Less valuation allowance	(5.6)	(45.3)
Deferred tax assets	157.2	240.2
Right of use assets	(48.3)	(44.1)
Fixed assets and intangible assets	(194.1)	(223.9)
Commissions	(18.2)	(16.8)
Pensions	(57.0)	(56.5)
Other	(18.9)	(12.8)
Deferred tax liabilities	(336.5)	(354.1)
Deferred tax liabilities, net	$ (179.3)	$ (113.9)