Financial instruments (Tables)

9 Months Ended

Oct. 01, 2017

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Fair Values of Derivative Instruments Designated as Hedging Instruments

The following table presents the locations in the condensed consolidated balance sheet and fair value of derivative financial instruments as of October 1, 2017 and December 31, 2016:

	October 1, 2017		December 31, 2016
	Fair Value
	(Dollars in thousands)
Asset derivatives:
Designated foreign currency forward contracts	$	1,684	$	667
Non-designated foreign currency forward contracts	318		490
Prepaid expenses and other current assets	$	2,002	$	1,157
Total asset derivatives	$	2,002	$	1,157
Liability derivatives:
Designated foreign currency forward contracts	$	237	$	2,139
Non-designated foreign currency forward contracts	93		118
Other current liabilities	$	330	$	2,257
Total liability derivatives	$	330	$	2,257

Aggregate Accounts Receivable, Net of Allowance for Doubtful Accounts

The following table provides information regarding the Company's allowance for doubtful accounts, the aggregate net current and long-term trade accounts receivable related to customers in Greece, Italy, Spain and Portugal and the percentage of the Company’s total net current and long-term trade accounts receivable represented by these customers' trade accounts receivable at October 1, 2017 and December 31, 2016:

	October 1, 2017			December 31, 2016
	(Dollars in thousands)
Allowance for doubtful accounts(1)	$	10,084		$	8,630
Current and long-term trade accounts receivable in Greece, Italy, Spain and Portugal (2)	$	50,613		$	51,098
Percentage of total net current and long-term trade accounts receivable - Greece, Italy, Spain and Portugal	16.9		%	19.3		%

(1) The current portion of the allowance for doubtful accounts was $3.1 million and $2.0 million as of October 1, 2017 and December 31, 2016, respectively, and was recognized in accounts receivable, net.

(2) The long-term portion of trade accounts receivable, net from customers in Greece, Italy, Spain and Portugal at October 1, 2017 and December 31, 2016 was $3.5 million and $2.7 million, respectively. In January 2017, the Company sold $16.1 million of receivables outstanding with respect to publicly funded hospitals in Italy for $16.0 million.