Receivables, net (Net components of receivables) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Receivables [Abstract]
Customers, trade	$ 794,691	$ 696,856
Income tax receivable	613	1,703
Other	29,477	31,311
Receivables, gross	824,781	729,870
Less allowance for discounts, returns, claims and doubtful accounts	42,659	43,705
Receivables, net	$ 782,122	$ 686,165