Reportable Segments (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Segment Reporting Information [Line Items]
Sales	$ 301,757	$ 254,249	$ 873,671	$ 710,294
Operating Income (Loss)	35,886	32,032	96,216	88,976
Energy & Chemicals [Member]
Segment Reporting Information [Line Items]
Sales	79,986	82,968	239,563	228,921
Operating Income (Loss)	14,493	17,057	42,226	44,785
Distribution & Storage [Member]
Segment Reporting Information [Line Items]
Sales	152,895	117,752	428,784	336,278
Operating Income (Loss)	22,337	19,948	65,019	54,447
BioMedical [Member]
Segment Reporting Information [Line Items]
Sales	68,876	53,529	205,324	145,095
Operating Income (Loss)	9,970	7,051	25,475	25,498
Corporate [Member]
Segment Reporting Information [Line Items]
Operating Income (Loss)	$ (10,914)	$ (12,024)	$ (36,504)	$ (35,754)