Income Taxes (Details) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Income Tax Contingency [Line Items]
Alternative minimum tax credit carryforwards	$ 31,600,000		$ 31,600,000
General business credits	1,600,000		1,600,000
State tax net operating loss carryforwards	3,300,000		3,300,000
Foreign net operating loss carryforward	51,600,000		51,600,000
Income tax benefit (provision)	2,464,000	$ (5,619,000)	8,127,000	$ (15,909,000)
Discrete income tax benefit, restructuring			10,600,000
Discrete income tax benefit, remeasurement of deferred state tax			$ 8,300,000
Deferred state tax rate			4.00%		10.60%
Interest and penalties accrued	0	$ 800,000	$ 0	800,000
Cash paid for income taxes			13,100,000	$ 14,200,000
Year 2016 to 2019 [Member]
Income Tax Contingency [Line Items]
Foreign net operating loss carryforward	18,100,000		18,100,000
Year 2024 to 2035 [Member]
Income Tax Contingency [Line Items]
Foreign net operating loss carryforward	25,400,000		25,400,000
Federal [Member]
Income Tax Contingency [Line Items]
Net operating loss carryforwards	104,800,000		104,800,000
Federal [Member] | Norilsk Nickel Change in Control [Member]
Income Tax Contingency [Line Items]
Net operating loss carryforwards	80,900,000		80,900,000
Annual limit on usage of net operating loss carryforwards	10,200,000		10,200,000
Foreign Tax Authority [Member]
Income Tax Contingency [Line Items]
Foreign net operating loss carryforward, not subject to expiration	$ 8,100,000		$ 8,100,000