Preferred Share Issuance and Merger - Net Identifiable Assets Acquired (Details) - USD ($) $ in Thousands	Sep. 30, 2015	May. 18, 2015	Dec. 31, 2014
Business Acquisition [Line Items]
Goodwill	$ 170,021		$ 420,129
BCP IV GrafTech Holdings LP [Member]
Business Acquisition [Line Items]
Cash		$ 25,032
Accounts receivable		94,298
Inventories		346,590
Property, Plant and Equipment		$ 652,371
Assets held for sale- net
Intangible assets		$ 158,500
Deferred tax assets		35,638
Other assets		49,716
Accounts Payable		(68,005)
Short-term debt		(18,779)
Other accrued liabilities		(52,421)
Long-term debt		(367,811)
Other long-term liabilities		(93,837)
Deferred tax liabilities		(85,801)
Net identifiable assets acquired		683,919
Goodwill		170,418
Net assets acquired		$ 854,337