Derivatives - Amount of Gain (Loss) Recognized in OCI and Income Statement (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain/(Loss) recognized in OCI									$ (9,523)	$ (5,456)	$ 64
Interest expense									(9,994)	(12,413)	(10,360)
Net sales	$ 258,004	$ 243,975	$ 218,371	$ 243,525	$ 257,922	$ 243,049	$ 255,532	$ 238,349	963,875	994,852	882,753
Cost of sales									(562,698)	(562,486)	(487,983)
Derivatives designated as cash flow hedges | Interest expense
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain/(Loss) reclassified from AOCI									(872)	2,040	1,537
Derivatives designated as cash flow hedges | Revenue
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain/(Loss) reclassified from AOCI									36	577	136
Derivatives designated as cash flow hedges | Cost of sales
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain/(Loss) reclassified from AOCI									(1,288)	(578)	361
Derivatives designated as cash flow hedges | Interest rate swap
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain/(Loss) recognized in OCI									(6,131)	(2,830)	1,559
Derivatives designated as cash flow hedges | Foreign currency forward contracts
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain/(Loss) recognized in OCI									$ (5,516)	$ (587)	$ 539