Note 4 - Accounts Receivable (Tables)

12 Months Ended

Dec. 31, 2017

Notes Tables

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

	2017			2016
Retail customers	$	22,227		$	17,511
Wholesale carriers		8,146			4,293
Other		4,891			4,373
		35,264			26,177
Less: allowance for doubtful accounts		(2,729	)		(1,115	)
Accounts receivable, net	$	32,535		$	25,062

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

	2017			2016			2015
Balance at January 1	$	1,115		$	1,693		$	2,338
Provision for uncollectible accounts		3,577			378			1,258
Charged to other accounts		(358	)		(13	)		8
Deductions		(1,605	)		(943	)		(1,911	)
Balance at December 31	$	2,729		$	1,115		$	1,693