Selected Balance Sheet Data, Accounts Receivable (Details) (USD $)	Sep. 30, 2013		Dec. 31, 2012
Accounts Receivable, Net
Accounts receivable	$ 52,596,000		$ 55,039,000
Less allowance for bad debts	(4,477,000)		(4,333,000)
Accounts receivable, net	48,119,000	[1]	50,706,000	[1]
Accounts receivable from affiliates, net	$ 14		$ 586

[1] Accounts receivable, net includes $14 and $586 due from affiliates as of Sept. 30, 2013 and Dec. 31, 2012, respectively.