Allowance For Doubtful Accounts (Impaired Notes Receivable) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Impaired Notes Receivable [Roll Forward]
Impaired Notes Receivable, Balance Beginning of Year	$ 1,855	$ 1,910	$ 2,900
Impaired Notes Receivable, Additions	0	5	676
Impaired Notes Receivable, Deductions	216	60	1,666
Impaired Notes Receivable, Balance End of Year	1,639	1,855	1,910
Impaired Notes Receivable, Average Outstanding Balance	$ 1,747	$ 1,883	$ 2,405