Condensed Financial Information (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Mar. 31, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Schedule of Equity Method Investments [Line Items]
Equity Method Investment	$ 25,191			$ 25,191		$ 22,817
Revenue Recognized Under Net Reporting Arrangements	11,200	$ 10,700		33,000	$ 32,800
Kelko (Venezuela) [Member]
Schedule of Equity Method Investments [Line Items]
Effect Of Currency Conversion, Amount	100		$ 100	400
Equity Method Investment	$ 100			$ 100