Segment Reporting Level 4 (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Segment Reporting Information [Line Items]
TOTAL ASSETS	$ 638,532	$ 562,901	$ 638,532	$ 562,901	$ 610,873
Capital expenditures	9,260	6,219	24,154	18,203
Depreciation and amortization	6,459	5,738	17,419	17,374
Total Revenue	245,428	231,344	726,625	663,862
Segment Reporting Information, Intersegment Revenue	0	0	0	0
OPERATING INCOME	75,380	63,564	221,412	177,866
Operating Segment Reservoir Description [Member]
Segment Reporting Information [Line Items]
TOTAL ASSETS	289,830	267,425	289,830	267,425
Capital expenditures	4,448	2,940	10,594	10,322
Depreciation and amortization	3,557	3,521	10,549	10,520
Total Revenue	124,156	119,853	366,724	346,232
Segment Reporting Information, Intersegment Revenue	638	446	1,934	1,262
OPERATING INCOME	36,780	28,780	107,271	81,847
Operating Segment Production Enhancement [Member]
Segment Reporting Information [Line Items]
TOTAL ASSETS	247,907	235,152	247,907	235,152
Capital expenditures	1,882	2,410	6,150	5,713
Depreciation and amortization	1,874	1,563	4,374	4,780
Total Revenue	100,871	97,407	297,151	268,292
Segment Reporting Information, Intersegment Revenue	972	232	2,055	897
OPERATING INCOME	32,339	30,728	95,434	78,490
Operating Segment Reservoir Management [Member]
Segment Reporting Information [Line Items]
TOTAL ASSETS	28,194	16,211	28,194	16,211
Capital expenditures	290	204	730	595
Depreciation and amortization	188	164	530	513
Total Revenue	20,401	14,084	62,750	49,338
Segment Reporting Information, Intersegment Revenue	295	377	1,099	1,331
OPERATING INCOME	6,029	3,502	21,057	17,473
Operating Segment Corporate And Other [Member]
Segment Reporting Information [Line Items]
TOTAL ASSETS	72,601	44,113	72,601	44,113
Capital expenditures	2,640	665	6,680	1,573
Depreciation and amortization	840	490	1,966	1,561
Total Revenue	0	0	0	0
Segment Reporting Information, Intersegment Revenue	(1,905)	(1,055)	(5,088)	(3,490)
OPERATING INCOME	$ 232	$ 554	$ (2,350)	$ 56