Note C - Significant Customers - Schedules of Concentration of Risk, by Risk Factor (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Accounts receivable, net of allowance of $1,193 in 2024 and $1,065 in 2023	$ 219,946	$ 215,581
Accounts Receivable [Member] | Customer Concentration Risk [Member] | Do D [Member]
Accounts receivable, net of allowance of $1,193 in 2024 and $1,065 in 2023	64,050	56,848
Accounts Receivable [Member] | Customer Concentration Risk [Member] | Amazon [Member]
Accounts receivable, net of allowance of $1,193 in 2024 and $1,065 in 2023	83,209	74,509
Accounts Receivable [Member] | Customer Concentration Risk [Member] | DHL [Member]
Accounts receivable, net of allowance of $1,193 in 2024 and $1,065 in 2023	$ 9,777	$ 8,040