Segment Reporting Level 4 (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Segment Reporting Information [Line Items]
TOTAL ASSETS	$ 655,116	$ 622,673	$ 655,116	$ 622,673	$ 636,516
Capital expenditures	9,492	7,597	17,935	14,894
Depreciation and amortization	5,964	5,077	11,989	10,960
Total Revenue	263,139	247,006	524,066	481,197
Segment Reporting Information, Intersegment Revenue	0	0	0	0
OPERATING INCOME	81,869	72,126	160,906	146,032
Operating Segment Reservoir Description [Member]
Segment Reporting Information [Line Items]
TOTAL ASSETS	299,399	279,823	299,399	279,823
Capital expenditures	6,424	3,667	11,853	6,146
Depreciation and amortization	3,599	3,445	7,224	6,992
Total Revenue	129,222	126,462	254,467	242,568
Segment Reporting Information, Intersegment Revenue	1,090	760	1,475	1,296
OPERATING INCOME	36,918	38,076	71,769	70,491
Operating Segment Production Enhancement [Member]
Segment Reporting Information [Line Items]
TOTAL ASSETS	255,987	246,837	255,987	246,837
Capital expenditures	1,851	2,426	3,939	4,268
Depreciation and amortization	1,797	902	3,614	2,500
Total Revenue	110,199	99,547	217,630	196,280
Segment Reporting Information, Intersegment Revenue	740	615	1,677	1,083
OPERATING INCOME	37,239	29,564	71,477	63,095
Operating Segment Reservoir Management [Member]
Segment Reporting Information [Line Items]
TOTAL ASSETS	35,570	24,756	35,570	24,756
Capital expenditures	517	29	1,036	440
Depreciation and amortization	189	175	380	342
Total Revenue	23,718	20,997	51,969	42,349
Segment Reporting Information, Intersegment Revenue	400	785	823	804
OPERATING INCOME	7,475	7,113	17,321	15,028
Operating Segment Corporate And Other [Member]
Segment Reporting Information [Line Items]
TOTAL ASSETS	64,160	71,257	64,160	71,257
Capital expenditures	700	1,475	1,107	4,040
Depreciation and amortization	379	555	771	1,126
Total Revenue	0	0	0	0
Segment Reporting Information, Intersegment Revenue	(2,230)	(2,160)	(3,975)	(3,183)
OPERATING INCOME	$ 237	$ (2,627)	$ 339	$ (2,582)