Accounts Receivable and Inventories (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended			6 Months Ended
	Jun. 30, 2012		Jun. 30, 2011	Jun. 30, 2012		Jun. 30, 2011	Dec. 31, 2011
Accounts receivable
Trade accounts receivable	$ 634,981			$ 634,981			$ 636,304
Less: Allowance for doubtful accounts	(19,783)			(19,783)			(17,829)
Trade accounts receivable, net	615,198			615,198			618,475
Other receivables	33,014	[1]		33,014	[1]		44,431	[1]
Provision for doubtful accounts related to trade accounts receivable	3,936		1,592	6,863		3,748
Inventories
Finished goods	83,754			83,754			78,445
Work-in-process	43,813			43,813			34,041
Raw materials and purchased parts	95,894			95,894			92,995
Stores and supplies	37,500			37,500			36,453
Inventories	$ 260,961			$ 260,961			$ 241,934

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