Accounts Receivable, net (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Accounts receivable, net
Gross accounts receivable	$ 111,315	$ 113,015
Allowance for doubtful accounts	(7,443)	(9,078)
Total accounts receivable, net	$ 103,872	$ 103,937