Note 9 - Segment Data (Detail) - Summary of Operating Results for Reportable Segments (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Revenues
Revenues	$ 245,756	$ 230,822	$ 508,092	$ 433,473
Operating Income (loss)
Operating Income (Loss)	24,755	31,596	50,890	59,544
Fluids Systems Engineering [Member]
Revenues
Revenues	202,388	191,205	420,884	361,672
Operating Income (loss)
Operating Income (Loss)	13,480	20,792	27,475	39,991
Mats Integrated Services [Member]
Revenues
Revenues	30,071	27,793	60,604	50,856
Operating Income (loss)
Operating Income (Loss)	13,075	14,730	27,414	26,514
Environmental Services [Member]
Revenues
Revenues	13,297	11,824	26,604	20,945
Operating Income (loss)
Operating Income (Loss)	3,514	2,980	7,089	4,600
Corporate Office [Member]
Operating Income (loss)
Operating Income (Loss)	$ (5,314)	$ (6,906)	$ (11,088)	$ (11,561)