Property And Equipment - (Details) - USD ($) |
Dec. 31, 2016 |
Dec. 31, 2015 |
|---|---|---|
| Property, Plant and Equipment [Line Items] | ||
| Asset Disposals, Pretax | $ 4,031,000 | |
| Property and equipment, gross | $ 397,230,000 | 395,005,000 |
| Less allowance for depreciation | (321,871,000) | (316,500,000) |
| Property and equipment, net | 75,359,000 | 78,505,000 |
| Machinery and equipment | ||
| Property, Plant and Equipment [Line Items] | ||
| Property and equipment, gross | 301,367,000 | 299,205,000 |
| Land, buildings and improvements | ||
| Property, Plant and Equipment [Line Items] | ||
| Property and equipment, gross | 73,709,000 | 73,830,000 |
| Furniture and fixtures | ||
| Property, Plant and Equipment [Line Items] | ||
| Property and equipment, gross | 10,100,000 | 10,023,000 |
| Leasehold improvements | ||
| Property, Plant and Equipment [Line Items] | ||
| Property and equipment, gross | $ 12,054,000 | $ 11,947,000 |