Segment Reporting Level 4 (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011
Segment Reporting Information [Line Items]
TOTAL ASSETS	$ 622,673	$ 552,233	$ 622,673	$ 552,233	$ 610,873
Capital expenditures	7,597	7,605	14,894	11,984
Depreciation and amortization	5,077	5,805	10,960	11,636
Total Revenue	247,006	225,785	481,197	432,518
Segment Reporting Information, Intersegment Revenue	0	0	0	0
OPERATING INCOME	72,126	57,803	146,032	114,302
Operating Segment Reservoir Description [Member]
Segment Reporting Information [Line Items]
TOTAL ASSETS	279,823	272,298	279,823	272,298
Capital expenditures	3,667	4,079	6,146	7,382
Depreciation and amortization	3,445	3,517	6,992	6,999
Total Revenue	126,462	118,758	242,568	226,379
Segment Reporting Information, Intersegment Revenue	760	447	1,296	816
OPERATING INCOME	38,076	26,629	70,491	53,067
Operating Segment Production Enhancement [Member]
Segment Reporting Information [Line Items]
TOTAL ASSETS	246,837	208,114	246,837	208,114
Capital expenditures	2,426	2,499	4,268	3,303
Depreciation and amortization	902	1,578	2,500	3,217
Total Revenue	99,547	88,787	196,280	170,885
Segment Reporting Information, Intersegment Revenue	615	357	1,083	665
OPERATING INCOME	29,564	24,500	63,095	47,762
Operating Segment Reservoir Management [Member]
Segment Reporting Information [Line Items]
TOTAL ASSETS	24,756	19,146	24,756	19,146
Capital expenditures	29	284	440	391
Depreciation and amortization	175	169	342	349
Total Revenue	20,997	18,240	42,349	35,254
Segment Reporting Information, Intersegment Revenue	785	595	804	954
OPERATING INCOME	7,113	7,307	15,028	13,971
Operating Segment Corporate And Other [Member]
Segment Reporting Information [Line Items]
TOTAL ASSETS	71,257	52,675	71,257	52,675
Capital expenditures	1,475	743	4,040	908
Depreciation and amortization	555	541	1,126	1,071
Total Revenue	0	0	0	0
Segment Reporting Information, Intersegment Revenue	(2,160)	(1,399)	(3,183)	(2,435)
OPERATING INCOME	$ (2,627)	$ (633)	$ (2,582)	$ (498)