Accounts Receivable and Allowance for Doubtful Accounts (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Summary of Accounts receivable
Accounts receivable	$ 31,109	$ 33,203
Allowance for doubtful accounts	(1,537)	(1,585)
Accounts receivable, net	$ 29,572	$ 31,618