Financial instruments (Tables)

12 Months Ended

Dec. 31, 2019

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Schedule of Derivative Instruments in Statement of Financial Position, Fair Value

The following table presents the locations in the consolidated balance sheets and fair value of derivative instruments as of December 31, 2019 and 2018:

	December 31, 2019		December 31, 2018
	Fair Value
	(Dollars in thousands)
Asset derivatives:
Designated foreign currency forward contracts	$	1,659	$	1,216
Non-designated foreign currency forward contracts	192		106
Cross-currency interest rate swap	21,575		14,728
Prepaid expenses and other current assets	23,426		16,050
Cross-currency interest rate swap	13,066		—
Other assets	13,066		—
Total asset derivatives	36,492		16,050
Liability derivatives:
Designated foreign currency forward contracts	1,285		524
Non-designated foreign currency forward contracts	102		264
Other current liabilities	1,387		788
Cross-currency interest rate swap	—		7,793
Other liabilities	—		7,793
Total liability derivatives	$	1,387	$	8,581