Employee Separation and Restructuring Costs (Narrative) (Details)	3 Months Ended		6 Months Ended			12 Months Ended
	Jun. 30, 2016 USD ($)	Jun. 30, 2015 USD ($)	Jun. 30, 2016 USD ($)	Dec. 31, 2015 facility	Jun. 30, 2015 USD ($)	Jun. 30, 2016 USD ($)	Dec. 31, 2013 office facility
Restructuring Cost and Reserve [Line Items]
Charged to expense	$ 4,800,000	$ 7,500,000	$ 11,900,000		$ 18,100,000
Accelerated depreciation costs			3,200,000		300,000
Selling and Administrative Expenses
Restructuring Cost and Reserve [Line Items]
Charged to expense	2,900,000	2,200,000	7,300,000		4,900,000
Cost of Sales
Restructuring Cost and Reserve [Line Items]
Charged to expense	1,900,000	5,300,000	4,600,000		13,200,000
DSS Manufacturing Facility Closure and Corporate Administrative Reduction | Facility Closing
Restructuring Cost and Reserve [Line Items]
Number of facilities closed | facility				2
Charged to expense	1,700,000		6,800,000			$ 23,900,000
Severance costs						8,300,000
Accelerated depreciation costs						9,000,000
Other associated restructuring costs						2,500,000
Expected remaining costs	3,300,000		3,300,000			3,300,000
DSS Manufacturing Facility Closure and Corporate Administrative Reduction | Asset and Deprecation Charges
Restructuring Cost and Reserve [Line Items]
Charged to expense						$ 13,100,000
Other North American Locations
Restructuring Cost and Reserve [Line Items]
Charged to expense	$ 2,200,000		2,800,000
Spartech | Facility Closing
Restructuring Cost and Reserve [Line Items]
Number of facilities closed | facility							7
Charged to expense		$ 5,700,000	$ 0		$ 15,000,000
Spartech | Administrative Office Closing
Restructuring Cost and Reserve [Line Items]
Number of facilities closed | office							1