Reportable Segments (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Segment Reporting Information [Line Items]
Sales	$ 293,841	$ 301,757	$ 866,891	$ 873,671
Operating Income (Loss)	40,355	35,886	96,545	96,216
Energy & Chemicals [Member]
Segment Reporting Information [Line Items]
Sales	98,759	79,986	277,859	239,563
Operating Income (Loss)	22,993	14,493	55,642	42,226
Distribution & Storage [Member]
Segment Reporting Information [Line Items]
Sales	140,203	152,895	418,830	428,784
Operating Income (Loss)	22,005	22,337	64,314	65,019
BioMedical [Member]
Segment Reporting Information [Line Items]
Sales	54,879	68,876	170,202	205,324
Operating Income (Loss)	5,960	9,970	15,779	25,475
Corporate [Member]
Segment Reporting Information [Line Items]
Operating Income (Loss)	$ (10,603)	$ (10,914)	$ (39,190)	$ (36,504)