Accounts Receivable and Inventories (Details) (USD $)	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Accounts Receivable, Net, Current [Abstract]
Trade accounts receivable	$ 617,517,000		$ 636,304,000
Less: Allowance for doubtful accounts	(17,253,000)		(17,829,000)
Trade accounts receivable, net	600,264,000		618,475,000
Other receivables	39,836,000	[1]	44,431,000	[1]
Provision for doubtful accounts related to trae accounts receivable	11,266,000		7,880,000		9,962,000
Inventories
Finished goods	69,904,000		78,445,000
Work-in-process	28,944,000		34,041,000
Raw materials and purchased parts	99,058,000		92,995,000
Stores and supplies	38,606,000		36,453,000
Total inventories	236,512,000		241,934,000
Valued at lower of cost or market:
LIFO basis	108,633,000		115,523,000
FIFO basis	14,641,000		13,087,000
Average cost basis	113,238,000		113,324,000
Total inventories	236,512,000		241,934,000
Excess of inventories valued at current costs over LIFO	28,500,000		28,600,000
Change in income as a result of LIFO basis inventory valuation over FIFO basis valuation	$ 100,000		$ 100,000		$ 400,000

[1] Other receivables include insurance claim receivables, employee receivables, tax claim receivables and other miscellaneous receivables not included in Trade accounts receivable, net.