Allowance for Doubtful Accounts (Impaired Notes Receivable) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Impaired Notes Receivable
Balance Beginning of Year	$ 2,892	$ 1,639	$ 1,855
Additions	9,124	1,267	0
Deductions	1,808	14	216
Balance End of Year	10,208	2,892	1,639
Average Outstanding Balance	$ 6,550	$ 2,266	$ 1,747