Condensed Financial Information (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended			9 Months Ended		12 Months Ended		3 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Jun. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2003	Dec. 31, 2013	Jun. 30, 2014 Kelko (Venezuela) [Member]	Mar. 31, 2013 Kelko (Venezuela) [Member]	Sep. 30, 2014 Kelko (Venezuela) [Member]	Mar. 31, 2014 Primex [Member]
Schedule of Equity Method Investments [Line Items]
Impact of Restatement on Opening Retained Earnings, Net of Tax											$ 335
Effect Of Currency Devaluation, Amount									357
Effect Of Currency Devaluation, Per Diluted Share									$ 0.03
Foreign Currency Transaction Gain (Loss), Realized	160	(635)		(824)	(840)			321
Effect Of Currency Transaction Gain (Loss) Per Diluted Share								$ 0.02
Equity Method Investment	21,149			21,149			19,397			1,644
Other Nonoperating Expense	71	63		167	157	2,000
Mineral oil excise tax refund			2,057
Mineral oil excise tax refund, interest			483
Revenue Recognized Under Net Reporting Arrangements	$ 11,829	$ 10,950		$ 33,328	$ 30,288