Note 2 - Trade Accounts Receivable

12 Months Ended

Dec. 31, 2017

2.	TRADE ACCOUNTS RECEIVABLE

The Company's receivables result primarily from the sale of transportation and logistics services. The

Company performs ongoing credit evaluations of its customers and generally does

not

require collateral for accounts receivable. Accounts receivable, which consist of both billed and unbilled receivables, are presented net of an allowance for doubtful accounts. Accounts outstanding longer than contractual payment terms are considered past due and are reviewed individually for collectability. Accounts receivable balances consist of the following components as of

December 31, 2017

and

2016:

	20 1 7			20 1 6
	( i n thousands)

Billed	$	51,236		$	48,538
Unbilled		9,154			8,599
Allowance for doubtful accounts		(1,335	)		(994	)

Total accounts receivable —net	$	59,055		$	56,143

An analysis of changes in the allowance

for doubtful accounts for the years ended

December 31, 2017,

2016,

and

2015

follows:

	20 1 7		20 1 6		20 1 5
	( i n thousands)

Balance —beginning of year	$	994	$	549	$	1,611
Provision for bad debts		341		445		151
Charge-offs		-		-		(1,231	)
Recoveries		-		-		18

Balance —end of year	$	1,335	$	994	$	549