Property, Plant and Equipment (Tables)

12 Months Ended

Dec. 31, 2017

Property, Plant and Equipment [Abstract]

Schedule of property, plant and equipment

Property, plant and equipment consist of the following at December 31:

	2017			2016
Land	$	4,027		$	4,027
Building and improvements	91,766			90,780
Machinery and equipment	219,675			205,674
Construction in progress	7,837			7,229
	323,305			307,710
Less:  Accumulated depreciation	(207,076		)	(185,681		)
	$	116,229		$	122,029

Schedule of future minimum lease payments for capital leases and operating leases

The aggregate future minimum lease commitments for leases at December 31, 2017 are as follows:

	Operating Leases		Capital Leases
2018	$	6,832	$	246
2019	6,117		246
2020	3,448		116
2021	2,239		—
2022	2,099		—
Thereafter	3,613		—