Schedule II - Valuation and Qualifying Accounts - (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accounts receivable allowance
Valuation allowance and reserves
Balance at Beginning of Period	$ 8,370	$ 5,748	$ 6,290
Additions Charged to Expense	1,332	2,180	1,192
Charged to Other Accounts	12,960	13,505	10,722
Charges Utilized (Write-off)	(13,909)	(13,063)	(12,456)
Balance at End of Period	8,753	8,370	5,748
Noncurrent other assets allowance
Valuation allowance and reserves
Balance at Beginning of Period	4,554	3,081
Charged to Other Accounts	3,209	2,826	3,914
Charges Utilized (Write-off)	(2,026)	(1,353)	(833)
Balance at End of Period	$ 5,737	$ 4,554	$ 3,081