Accounts Receivable and Inventories (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended			9 Months Ended
	Sep. 30, 2014		Sep. 30, 2013	Sep. 30, 2014		Sep. 30, 2013	Dec. 31, 2013
Accounts receivable
Trade accounts receivable	$ 391,356			$ 391,356			$ 359,819
Less: Allowance for doubtful accounts	(13,083)			(13,083)			(6,638)
Trade accounts receivable, net	378,273			378,273			353,181
Other receivables	31,041	[1]		31,041	[1]		46,470	[1]
Provision for doubtful accounts related to trade accounts receivable	(170)		1,059	7,176		5,897
Inventories
Finished goods	32,455			32,455			23,112
Work-in-process	31,299			31,299			25,623
Raw materials and purchased parts	83,957			83,957			72,118
Stores and supplies	35,122			35,122			34,836
Inventories	$ 182,833			$ 182,833			$ 155,689

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