Accounts Receivable (Details) (USD $)	3 Months Ended	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2012	Dec. 31, 2012 Allowance for Doubtful Accounts and Sales Returns [Member]	Dec. 31, 2011 Allowance for Doubtful Accounts and Sales Returns [Member]	Dec. 31, 2010 Allowance for Doubtful Accounts and Sales Returns [Member]
Changes in allowance for doubtful accounts and sales returns [Abstract]
Balance at beginning of period		$ 1,763,000	$ 4,080,000	$ 1,322,000	$ 1,287,000
Net Additions Charged to Revenue and Expenses			10,523,000	2,766,000	593,000
Deductions			(529,000)	(8,000)	(558,000)
Balance at end of period	1,763,000	1,763,000	14,074,000	4,080,000	1,322,000
Uncollectible Contracts Receivable Losses Provision For Losses	7,855,000	12,051
Net Income Loss Attributable To Changes In Estimates Of Bad Debts And Sales Returns		$ 7,855,000
Net Income Loss Attributable To Changes In Estimates Of Bad Debts And Sales Returns Per Share	$ 0.15	$ 0.09