Condensed Financial Information (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended		12 Months Ended		3 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2003	Dec. 31, 2013	Jun. 30, 2014 Kelko (Venezuela) [Member]	Mar. 31, 2013 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	(185)	(238)	(984)	(205)			321
Effect Of Currency Transaction Gain (Loss) Per Diluted Share							$ 0.02
Equity Method Investment	21,416		21,416			19,397	1,433
Other Nonoperating Expense	47	62	101	108	2,000
Mineral oil excise tax refund		2,057
Mineral oil excise tax refund, interest		483
Revenue Recognized Under Net Reporting Arrangements	$ 10,926	$ 10,560	$ 21,499	$ 19,338