Reportable Segments (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012 segments	Mar. 31, 2011
Segment Reporting Information [Line Items]
Number of reportable segments	3
Sales	$ 216,106	$ 162,941
Operating income (loss)	23,861	14,307
Energy & Chemicals [Member]
Segment Reporting Information [Line Items]
Sales	68,824	42,516
Operating income (loss)	13,192	3,753
Distribution & Storage [Member]
Segment Reporting Information [Line Items]
Sales	105,092	73,373
Operating income (loss)	18,732	11,521
BioMedical [Member]
Segment Reporting Information [Line Items]
Sales	42,190	47,052
Operating income (loss)	4,592	8,447
Corporate [Member]
Segment Reporting Information [Line Items]
Sales	0	0
Operating income (loss)	$ (12,655)	$ (9,414)