Inventories (Details) (USD $)	Mar. 31, 2012	Dec. 31, 2011
Gross inventories @ FIFO:
Finished goods	$ 16,389,000	$ 11,914,000
Work in progress	32,223,000	27,749,000
Raw materials & component parts	164,542,000	144,731,000
Maintenance, tooling & supplies	17,062,000	17,001,000
Total gross inventories @ FIFO	230,216,000	201,395,000
Less reserves:
LIFO	33,103,000	32,103,000
Valuation	4,549,000	3,144,000
Total inventories as reported	192,564,000	166,148,000
Gross inventories on FIFO basis accounted for on a LIFO basis	$ 110,800,000	$ 97,900,000