Inventories (Details) (USD $)	Jun. 30, 2011	Dec. 31, 2010
Gross inventories @ FIFO [Abstract]
Finished goods	$ 8,075,000	$ 7,757,000
Work in progress	35,663,000	26,680,000
Raw materials & component parts	122,692,000	99,440,000
Maintenance, tooling & supplies	15,226,000	14,156,000
Total gross inventories @ FIFO	181,656,000	148,033,000
Less reserves [Abstract]
LIFO	31,458,000	28,776,000
Valuation	2,661,000	2,383,000
Total inventories as reported	147,537,000	116,874,000
Gross inventories on FIFO basis accounted for on a LIFO basis	$ 105,700,000	$ 80,900,000