Reportable Segments (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Segment Reporting Information [Line Items]
Assets	$ 1,323,236		$ 1,323,236		$ 1,174,475
Sales	254,249	211,311	710,294	574,950
Operating Income (Loss)	32,032	29,043	88,976	64,839
Energy & Chemicals [Member]
Segment Reporting Information [Line Items]
Assets	237,381		237,381		203,067
Sales	82,968	57,777	228,921	149,414
Operating Income (Loss)	17,057	12,584	44,785	21,941
Distribution & Storage [Member]
Segment Reporting Information [Line Items]
Assets	580,284		580,284		556,688
Sales	117,752	100,911	336,278	275,966
Operating Income (Loss)	19,948	16,109	54,447	44,731
BioMedical [Member]
Segment Reporting Information [Line Items]
Assets	456,384		456,384		226,729
Sales	53,529	52,623	145,095	149,570
Operating Income (Loss)	7,051	8,548	25,498	24,218
Corporate [Member]
Segment Reporting Information [Line Items]
Assets	49,187		49,187		187,991
Sales	0	0	0	0
Operating Income (Loss)	$ (12,024)	$ (8,198)	$ (35,754)	$ (26,051)