Continued Dumping and Subsidy Act (Details Textual) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Jul. 01, 2016	Apr. 01, 2016
CDSOA [Abstract]
Continued Dumping & Subsidy Offset Act (CDSOA) receipts, net of expense	$ 0	$ 6,100,000	$ 0	$ 53,800,000
Continued Dumping and Subsidy Offset Act, distributions					$ 6,300,000	$ 48,100,000