Reportable Segments (Details) - USD ($) $ in Thousands		3 Months Ended			9 Months Ended
		Sep. 30, 2016		Sep. 30, 2015	Sep. 30, 2016		Sep. 30, 2015
Segment Reporting Information [Line Items]
Sales		$ 203,930		$ 264,047	$ 644,782		$ 779,404
Operating Income (Loss)		20,064		15,609	55,040		55,695
Energy & Chemicals [Member]
Segment Reporting Information [Line Items]
Sales		23,711		78,388	122,865		257,197
Operating Income (Loss)	[1]	(5,736)		10,795	14,190		45,626
Distribution & Storage [Member]
Segment Reporting Information [Line Items]
Sales		126,646		129,590	363,743		356,474
Operating Income (Loss)	[1]	14,715		8,027	37,550		29,184
BioMedical [Member]
Segment Reporting Information [Line Items]
Sales		53,573		56,069	158,174		165,733
Operating Income (Loss)	[1]	20,916	[2]	5,966	38,120	[2]	15,202
Corporate [Member]
Segment Reporting Information [Line Items]
Operating Income (Loss)	[1]	(9,831)	[2]	$ (9,179)	(34,820)	[2]	$ (34,317)
Cost of Sales [Member]
Segment Reporting Information [Line Items]
Gain (Loss) Related to Litigation Settlement		15,145			15,145
Selling, General and Administrative Expenses [Member]
Segment Reporting Information [Line Items]
Gain (Loss) Related to Litigation Settlement		$ 859			$ 376

[1] As described in Note 1, beginning in 2016, the Company allocates share-based compensation expense to each operating segment and maintains share-based compensation expense related to Corporate employees at Corporate. Prior to 2016, all share-based compensation expense was recorded at Corporate. Reclassifications from Corporate to the operating segments have been made to the 2015 results to conform to the 2016 presentation.

[2] During the third quarter of 2016, the Company recovered for breaches of representations and warranties primarily related to warranty costs for certain product lines acquired in the 2012 acquisition of AirSep Corporation under the related representation and warranty insurance. For the three months ended September 30, 2016, this reduced our BioMedical segment’s cost of sales by $15,145 and Corporate SG&A expenses by $859, net of associated legal fees. For the nine months ended September 30, 2016, this reduced our BioMedical segment’s cost of sales by $15,145 and Corporate SG&A expenses by $376, net of associated legal fees recorded in the first nine months of the year.