ACCOUNTS RECEIVABLE

12 Months Ended

Dec. 31, 2017

Accounts Receivable, Net [Abstract]

ACCOUNTS RECEIVABLE

7.    ACCOUNTS RECEIVABLE

Accounts receivable comprised the following at December 31, 2017 and December 31, 2016:

	December 31, 2017			December 31, 2016
Third-party customers	$	168,805		$	149,957
Less: allowance for bad debts and credit notes	(9,902		)	(8,586		)
Total accounts receivable	$	158,903		$	141,371

Bad debt expense for the years ended December 31, 2017, 2016 and 2015 was US$ 1.9 million, US$ 3.7 million, and US$ 2.3 million, respectively.