Segment Reporting Level 4 (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Dec. 31, 2011
Segment Reporting Information [Line Items]
TOTAL ASSETS	$ 610,678	$ 597,274	$ 605,139
Capital expenditures	7,297	4,379
Depreciation and amortization	5,883	5,831
Total Revenue	234,191	206,733
Segment Reporting Information, Intersegment Revenue	0	0
OPERATING INCOME	73,906	56,499
Operating Segment Reservoir Description [Member]
Segment Reporting Information [Line Items]
TOTAL ASSETS	271,320	271,875
Capital expenditures	2,479	3,303
Depreciation and amortization	3,547	3,482
Total Revenue	116,106	107,621
Segment Reporting Information, Intersegment Revenue	536	369
OPERATING INCOME	32,415	26,438
Operating Segment Production Enhancement [Member]
Segment Reporting Information [Line Items]
TOTAL ASSETS	248,866	201,970
Capital expenditures	1,842	804
Depreciation and amortization	1,598	1,639
Total Revenue	96,733	82,098
Segment Reporting Information, Intersegment Revenue	468	308
OPERATING INCOME	33,531	23,262
Operating Segment Reservoir Management [Member]
Segment Reporting Information [Line Items]
TOTAL ASSETS	24,191	24,967
Capital expenditures	411	107
Depreciation and amortization	167	180
Total Revenue	21,352	17,014
Segment Reporting Information, Intersegment Revenue	19	359
OPERATING INCOME	7,915	6,664
Operating Segment Corporate And Other [Member]
Segment Reporting Information [Line Items]
TOTAL ASSETS	66,301	98,462
Capital expenditures	2,565	165
Depreciation and amortization	571	530
Total Revenue	0	0
Segment Reporting Information, Intersegment Revenue	(1,023)	(1,036)
OPERATING INCOME	$ 45	$ 135