Schedule II-Valuation And Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Allowance for Trade Receivables [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	$ 8,718	$ 10,084	$ 12,187
Additions/Charges to Profit & Loss	5,083	4,382	4,090
Recoveries/Write offs	(5,244)	(5,748)	(6,193)
Balance at End of Period	8,557	8,718	10,084
Allowance for Notes Receivable [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	6,765	5,987	11,546
Additions/Charges to Profit & Loss	2,319	1,742	2,630
Recoveries/Write offs	(1,654)	(964)	(8,189)
Balance at End of Period	$ 7,430	$ 6,765	$ 5,987