Selected Balance Sheet Data, Accounts Receivable (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012
Accounts Receivable, Net
Accounts receivable	$ 64,180		$ 55,039
Less allowance for bad debts	(4,911)		(4,333)
Accounts receivable, net	59,269	[1]	50,706	[1]
Accounts receivable from affiliates, net	$ 1,595		$ 586

[1] Accounts receivable, net includes $1,595 and $586 due from affiliates as of Dec. 31, 2013 and 2012, respectively.