Business Segment, Geographic and Major Customer Information - Reportable Segments (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Summarized financial information regarding reportable segments
Net revenue from external customers	$ 78,243	$ 79,195
Gross margin	32,630	33,451
Income (loss) from operations	12,548	16,748
Depreciation and amortization	3,033	2,648
Total assets	218,483	204,192	219,867
Capital expenditures	4,383	4,119
Chemicals and Logistics [Member]
Summarized financial information regarding reportable segments
Net revenue from external customers	44,650	47,647
Gross margin	19,113	20,895
Income (loss) from operations	14,324	17,122
Depreciation and amortization	460	404
Total assets	59,301	59,913
Capital expenditures	1,025	1,250
Drilling Products [Member]
Summarized financial information regarding reportable segments
Net revenue from external customers	28,914	28,988
Gross margin	11,346	11,509
Income (loss) from operations	5,419	5,549
Depreciation and amortization	2,362	2,158
Total assets	120,015	115,401
Capital expenditures	861	2,394
Artificial Lift [Member]
Summarized financial information regarding reportable segments
Net revenue from external customers	4,679	2,560
Gross margin	2,171	1,047
Income (loss) from operations	1,613	516
Depreciation and amortization	61	44
Total assets	12,280	10,907
Capital expenditures	997	13
Corporate [Member]
Summarized financial information regarding reportable segments
Net revenue from external customers	0	0
Gross margin	0	0
Income (loss) from operations	(8,808)	(6,439)
Depreciation and amortization	150	42
Total assets	26,887	17,971
Capital expenditures	$ 1,500	$ 462