Accounts Receivable and Inventories (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014	Dec. 31, 2014
Accounts receivable
Trade accounts receivable	$ 346,241			$ 340,223
Less: Allowance for doubtful accounts	(14,236)			(15,119)
Trade accounts receivable, net	332,005			325,104
Other receivables	21,709	[1]		28,145	[1]
Provision for doubtful accounts related to trade accounts receivable	196		(19)
Inventories
Finished goods	33,480			30,525
Work-in-process	43,261			28,690
Raw materials and purchased parts	85,599			87,985
Stores and supplies	32,258			31,722
Inventories	$ 194,598			$ 178,922

[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.