Trade Accounts Receivable, Net (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2013
Receivables [Abstract]
Trade accounts receivable	$ 141,565	$ 92,413	$ 130,612
Allowance for doubtful accounts	(936)	(945)	(1,141)
Allowance for sales discounts and returns	(2,826)	(1,451)	(2,583)
Trade accounts receivable, net	$ 137,803	$ 90,017	$ 126,888