Operating Units Other Segments (Details)	6 Months Ended
	Jun. 30, 2016 real_estate_properties distribution_centers real_estate_property_units manufacturing_facilities
Real Estate Segment [Member]
Segment Reporting Information [Line Items]
Number of Real Estate commercial rental properties | real_estate_properties	15
Ferrous Resources [Member]
Segment Reporting Information [Line Items]
Percentage of equity ownership in subsidiary	77.20%
ARI [Member]
Segment Reporting Information [Line Items]
Percentage of equity ownership in subsidiary	61.20%
Viskase [Member]
Segment Reporting Information [Line Items]
Percentage of equity ownership in subsidiary	73.30%
Number of Manufacturing Facilities | manufacturing_facilities	9
Number of Distribution Centers | distribution_centers	6
Net sales from customers located outside the U.S.	69.00%
MASSACHUSETTS | Real Estate Segment [Member]
Segment Reporting Information [Line Items]
Number of units of residential housing in future development	239
FLORIDA | Real Estate Segment [Member]
Segment Reporting Information [Line Items]
Number of units of residential housing in future development	1,128