Note 9 - Segment Data (Detail) - Summary of Operating Results for Reportable Segments (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Revenues
Revenues	$ 259,599	$ 261,193	$ 767,691	$ 694,666
Operating Income (loss)
Operating Income (Loss)	28,756	39,179	79,646	98,723
Fluids Systems Engineering [Member]
Revenues
Revenues	211,457	216,160	632,341	577,832
Operating Income (loss)
Operating Income (Loss)	14,798	25,648	42,273	65,639
Mats Integrated Services [Member]
Revenues
Revenues	35,067	30,179	95,671	81,035
Operating Income (loss)
Operating Income (Loss)	15,992	14,509	43,406	41,023
Environmental Services [Member]
Revenues
Revenues	13,075	14,854	39,679	35,799
Operating Income (loss)
Operating Income (Loss)	3,089	4,958	10,178	9,558
Corporate Office [Member]
Operating Income (loss)
Operating Income (Loss)	$ (5,123)	$ (5,936)	$ (16,211)	$ (17,497)