Schedule II -- Valuation and Qualifying Accounts (Details) - Allowance for Doubtful Accounts - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	$ 59,689	$ 66,405	$ 17,735
Write-Off of Receivables	(41,758)	(47,758)	(30,877)
Charged to Costs and Expenses	26,799	41,042	79,547
Balance at End of Period	$ 44,730	$ 59,689	$ 66,405