Organization and Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2018

Inventories consisted of the following:



	As of December 31,
(Dollars in thousands)	2018		2017
Raw materials	$	59,321	$	43,092
Work-in-process	30,086		28,133
Finished goods	43,230		41,332
Total inventories	$	132,637	$	112,557

Schedule of property, plant and equipment, estimated useful lives

For financial reporting purposes, provisions for depreciation are calculated on a straight-line basis over the following estimated useful lives of the underlying assets:



Property, Plant and Equipment Classification	Estimated Useful Lives
Buildings and improvements	30-40 years
Machinery and equipment	5-15 years
Office equipment	3-10 years



	As of December 31,
(Dollars in thousands)	2018			2017
Land	$	21,525		$	14,620
Buildings and improvements	175,279			135,191
Machinery and equipment	256,301			238,000
Office equipment	64,886			56,554
Property plant and equipment, gross	517,991			444,365
Accumulated depreciation	(317,414		)	(289,909		)
Property, plant and equipment, net	200,577			154,456
Equipment in process	42,182			25,155
Total property, plant and equipment, net	$	242,759		$	179,611