Slicers (applies to each fact value in each table cell)

Reporting Entity [Axis]

0000863436 (http://www.sec.gov/CIK)

Property Plant And Equipment [Abstract]	Period [Axis]
	2016-01-01 - 2016-12-31
Property Plant And Equipment [Abstract]
Schedule Of Property, Plant And Equipment	December 31, (in thousands) 2016 2015 Land $ 6,169 $ 6,169 Buildings and building improvements 90,330 89,720 Machinery and equipment 445,537 432,582 Furniture and fixtures 8,089 8,049 Vehicles 1,231 1,009 Leasehold improvements 21,167 19,729 572,523 557,258 Less accumulated depreciation (406,375) (379,088) $ 166,148 $ 178,170