Reportable Segments (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Segment Reporting Information [Line Items]
Sales	$ 298,266	$ 239,939	$ 571,914	$ 456,045
Operating Income (Loss)	32,979	33,083	60,330	56,944
Energy & Chemicals [Member]
Segment Reporting Information [Line Items]
Sales	78,716	77,129	159,577	145,953
Operating Income (Loss)	14,914	14,536	27,733	27,728
Distribution & Storage [Member]
Segment Reporting Information [Line Items]
Sales	147,156	113,434	275,889	218,526
Operating Income (Loss)	23,393	17,674	42,682	34,499
BioMedical [Member]
Segment Reporting Information [Line Items]
Sales	72,394	49,376	136,448	91,566
Operating Income (Loss)	8,752	11,948	15,505	18,447
Corporate [Member]
Segment Reporting Information [Line Items]
Sales	0	0	0	0
Operating Income (Loss)	$ (14,080)	$ (11,075)	$ (25,590)	$ (23,730)