Allowance For Doubtful Accounts (Reserve For Impaired Notes Receivable) (Details) (USD $)	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Allowance For Doubtful Accounts [Abstract]
Reserve for Impaired Notes Receivable, Balance Beginning of Year	$ 1,066,000	$ 930,000	$ 2,100,000	$ 1,300,000
Reserve for Impaired Notes Receivable, Additions	196,000	496,000	900,000
Reserve for Impaired Notes Receivable, Deductions	60,000	1,666,000	100,000
Reserve for Impaired Notes Receivable, Balance End of Year	$ 1,066,000	$ 930,000	$ 2,100,000	$ 1,300,000