Note 4 - Accounts Receivable (Tables)

12 Months Ended

Dec. 31, 2019

Notes Tables

Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block]

	2019			2018
Retail customers	$	22,101		$	21,732
Wholesale carriers		13,157			9,315
Other		3,723			4,361
		38,981			35,408
Less: allowance for doubtful accounts		(4,627	)		(3,936	)
Accounts receivable, net	$	34,354		$	31,472

Changes in the Allowance for Doubtful Accounts [Table Text Block]

	2019			2018
Balance at January 1	$	3,936		$	2,729
Provision for uncollectible accounts		257			2,745
Charged to other accounts		1,253			(921	)
Deductions		(819	)		(617	)
Balance at December 31	$	4,627		$	3,936