Receivables, net (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Receivables [Abstract]
Customers, trade	$ 1,674,518	$ 1,538,348
Income tax receivable	9,400	9,835
Other	96,871	96,079
Receivables, gross	1,780,789	1,644,262
Less: allowance for discounts, returns, claims and doubtful accounts	90,877	86,103
Receivables, net	$ 1,689,912	$ 1,558,159